drm/plane: Fix a couple of checkpatch warnings

Code should be indented using tabs rather than spaces (see CodingStyle)
and the canonical form to declare a constant static variable is using
"static const" rather than "const static". Fixes the following warnings
from checkpatch:

	$ scripts/checkpatch.pl -f drivers/gpu/drm/drm_plane_helper.c
	WARNING: storage class should be at the beginning of the declaration
	#40: FILE: drivers/gpu/drm/drm_plane_helper.c:40:
	+const static uint32_t safe_modeset_formats[] = {

	WARNING: please, no spaces at the start of a line
	#41: FILE: drivers/gpu/drm/drm_plane_helper.c:41:
	+       DRM_FORMAT_XRGB8888,$

	WARNING: please, no spaces at the start of a line
	#42: FILE: drivers/gpu/drm/drm_plane_helper.c:42:
	+       DRM_FORMAT_ARGB8888,$
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_plane_helper.c

@@ -37,9 +37,9 @@
  * creating the primary plane.  However drivers that still call
  * drm_plane_init() will use this minimal format list as the default.
  */
-const static uint32_t safe_modeset_formats[] = {
-       DRM_FORMAT_XRGB8888,
-       DRM_FORMAT_ARGB8888,
+static const uint32_t safe_modeset_formats[] = {
+	DRM_FORMAT_XRGB8888,
+	DRM_FORMAT_ARGB8888,
 };
 
 /*