targets: export radeon winsys_create functions to silence LLVM warning

It silences the following radeonsi LLVM warning due to a previous
commit adding an LLVM workaround:
  "mesa: for the -simplifycfg-sink-common option: may only occur zero or one
   times!"

Cc: 17.0 <mesa-stable@lists.freedesktop.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by; Emil Velikov <emil.velikov@collabora.com>

src/gallium/targets/omx/omx.sym

@@ -1,6 +1,11 @@
 {
 	global:
 		omx_component_library_Setup;
+
+		# Workaround for an LLVM warning with -simplifycfg-sink-common
+		# due to LLVM being initialized multiple times.
+		radeon_drm_winsys_create;
+		amdgpu_winsys_create;
 	local:
 		*;
 };

src/gallium/targets/pipe-loader/pipe.sym

@@ -2,6 +2,11 @@
 	global:
 		driver_descriptor;
 		swrast_driver_descriptor;
+
+		# Workaround for an LLVM warning with -simplifycfg-sink-common
+		# due to LLVM being initialized multiple times.
+		radeon_drm_winsys_create;
+		amdgpu_winsys_create;
 	local:
 		*;
 };

src/gallium/targets/va/va.sym

@@ -1,6 +1,11 @@
 {
 	global:
 		__vaDriverInit_*_*;
+
+		# Workaround for an LLVM warning with -simplifycfg-sink-common
+		# due to LLVM being initialized multiple times.
+		radeon_drm_winsys_create;
+		amdgpu_winsys_create;
 	local:
 		*;
 };