drm/amdgpu: integer overflow in amdgpu_mode_dumb_create()

args->size is a u64.  arg->pitch and args->height are u32.  The
multiplication will overflow instead of using the high 32 bits as
intended.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c

@@ -659,7 +659,7 @@ int amdgpu_mode_dumb_create(struct drm_file *file_priv,
 	int r;
 
 	args->pitch = amdgpu_align_pitch(adev, args->width, args->bpp, 0) * ((args->bpp + 1) / 8);
-	args->size = args->pitch * args->height;
+	args->size = (u64)args->pitch * args->height;
 	args->size = ALIGN(args->size, PAGE_SIZE);
 
 	r = amdgpu_gem_object_create(adev, args->size, 0,