drm/amd: Mark some tables as const

This patch marks some compile-time constant tables 'const'.
The tables marked in this patch are the low hanging fruit
where little other changes were necesary to avoid casting
away constness etc. Also mark some tables that are private
to a file as static.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Nils Wallménius <nils.wallmenius@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 66e51f9..5d05b5d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -2348,7 +2348,7 @@
  * KMS
  */
 extern const struct drm_ioctl_desc amdgpu_ioctls_kms[];
-extern int amdgpu_max_kms_ioctl;
+extern const int amdgpu_max_kms_ioctl;
 
 int amdgpu_driver_load_kms(struct drm_device *dev, unsigned long flags);
 int amdgpu_driver_unload_kms(struct drm_device *dev);