tu: fix -Wmissing-prototypes errors

Fixes:

src/freedreno/vulkan/tu_shader.cc:134:1: error:
  no previous prototype for function 'tu_init_softfloat32'[-Werror,-Wmissing-prototypes]
  134 | tu_init_softfloat32(struct tu_device *dev)
      | ^

Reviewed-by: Valentine Burley <valentine.burley@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/41518>

src/freedreno/vulkan/tu_acceleration_structure.cc

@@ -140,7 +140,7 @@ get_bvh_layout(VkGeometryTypeKHR geometry_type,
    layout->size = offset;
 }
 
-VkDeviceSize
+static VkDeviceSize
 get_bvh_size(VkDevice device,
              const struct vk_acceleration_structure_build_state *state)
 {

src/freedreno/vulkan/tu_device.cc

@@ -2491,7 +2491,7 @@ fail:
    return vk_error(device->instance, VK_ERROR_OUT_OF_HOST_MEMORY);
 }
 
-void
+static void
 tu_free_copy_timestamp_data(struct tu_device *device,
                             struct tu_copy_timestamp_data *data)
 {
@@ -2739,7 +2739,7 @@ tu_device_get_timestamp(struct vk_device *vk_device, uint64_t *timestamp)
    return ret == 0 ? VK_SUCCESS : VK_ERROR_UNKNOWN;
 }
 
-void
+static void
 tu_device_destroy_mutexes(struct tu_device *device)
 {
    mtx_destroy(&device->bo_mutex);
@@ -3984,7 +3984,7 @@ tu_get_msrtss_temporary(struct tu_device *dev,
  * framebuffer with render passes or the command buffer with dynamic
  * rendering.
  */
-VkResult
+static VkResult
 tu_init_msrtss_attachments(struct tu_device *device,
                            const struct tu_render_pass *pass,
                            const struct tu_framebuffer *fb,

src/freedreno/vulkan/tu_knl_drm_msm.cc

@@ -474,7 +474,7 @@ tu_wait_fence(struct tu_device *dev,
    return VK_SUCCESS;
 }
 
-VkResult
+static VkResult
 msm_queue_wait_fence(struct tu_queue *queue, uint32_t fence,
                      uint64_t timeout_ns)
 {
@@ -769,7 +769,7 @@ tu_allocate_iova(struct tu_device *dev,
    return result;
 }
 
-void
+static void
 tu_free_iova(struct tu_device *dev,
              uint64_t iova,
              uint64_t size)

src/freedreno/vulkan/tu_knl_drm_virtio.cc

@@ -443,7 +443,7 @@ out:
    return VK_ERROR_UNKNOWN;
 }
 
-VkResult
+static VkResult
 virtio_queue_wait_fence(struct tu_queue *queue, uint32_t fence,
                         uint64_t timeout_ns)
 {

src/freedreno/vulkan/tu_knl_kgsl.cc

@@ -786,7 +786,7 @@ wait_timestamp_safe(int fd,
    }
 }
 
-VkResult
+static VkResult
 kgsl_queue_wait_fence(struct tu_queue *queue, uint32_t fence,
                       uint64_t timeout_ns)
 {

src/freedreno/vulkan/tu_nir_lower_ray_query.cc

@@ -522,7 +522,7 @@ lower_rq_load(nir_builder *b, struct hash_table *ht, nir_intrinsic_instr *intr)
  */
 #define TU_BVH_NO_INSTANCE_ROOT 0xfffffffeu
 
-nir_def *
+static nir_def *
 nir_build_vec3_mat_mult(nir_builder *b, nir_def *vec, nir_def *matrix[], bool translation)
 {
    nir_def *result_components[3] = {

src/freedreno/vulkan/tu_perfetto.cc

@@ -457,7 +457,7 @@ extern "C" {
 
 static once_flag tu_perfetto_init_once_flag = ONCE_FLAG_INIT;
 
-void
+static void
 tu_perfetto_init_once()
 {
    {

src/freedreno/vulkan/tu_shader.cc

@@ -130,7 +130,7 @@ static const uint32_t float32_spv[] = {
 
 #include "float64_spv.h"
 
-void
+static void
 tu_init_softfloat32(struct tu_device *dev)
 {
    if (dev->float32_shader)
@@ -144,7 +144,7 @@ tu_init_softfloat32(struct tu_device *dev)
    mtx_unlock(&dev->softfloat_mutex);
 }
 
-void
+static void
 tu_init_softfloat64(struct tu_device *dev)
 {
    if (dev->float64_shader)