freedreno: fix PIPE_CAP_MAX_TEXTURE_ARRAY_LAYERS for a6xx

We're reporting 2048 for VkPhysicalDeviceLimits::maxImageArrayLayers on
Turnip, so we should be able to use 2048 for OpenGL as well. And that's
the minimum required value for OpenGL 4.1 support.

According to http://vulkan.gpuinfo.org/, it seems like values of 2048
should be possible for at least as low as some Adreno 4xx GPUs. But
since we don't support recent GL versions on those, we this won't make a
big difference. So let's leave that up to someone who actually knows
what they're doing!

Acked-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19780>

src/freedreno/ci/freedreno-a618-fails.txt

@@ -34,8 +34,6 @@ KHR-GL45.texture_cube_map_array.color_depth_attachments,Fail
 #
 
 # Various limits we cannot or do not support:
-KHR-GL45.limits.max_array_texture_layers,Fail
-KHR-GL45.limits.max_framebuffer_layers,Fail
 KHR-GL45.limits.max_vertex_streams,Fail
 
 # Shader compile fails:

src/freedreno/ci/freedreno-a630-fails.txt

@@ -34,8 +34,6 @@ KHR-GL45.texture_cube_map_array.color_depth_attachments,Fail
 #
 
 # Various limits we cannot or do not support:
-KHR-GL45.limits.max_array_texture_layers,Fail
-KHR-GL45.limits.max_framebuffer_layers,Fail
 KHR-GL45.limits.max_vertex_streams,Fail
 
 # Shader compile fails:

src/gallium/drivers/freedreno/freedreno_screen.c

@@ -509,8 +509,9 @@ fd_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
       return 12;
 
    case PIPE_CAP_MAX_TEXTURE_ARRAY_LAYERS:
-      return (is_a3xx(screen) || is_a4xx(screen) || is_a5xx(screen) ||
-              is_a6xx(screen))
+      if (is_a6xx(screen))
+         return 2048;
+      return (is_a3xx(screen) || is_a4xx(screen) || is_a5xx(screen))
                 ? 256
                 : 0;