drm/Kconfig: rename keembay config

This all caps looked ugly.
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/kmb/Kconfig

 config DRM_KMB_DISPLAY
-	tristate "INTEL KEEMBAY DISPLAY"
+	tristate "Intel Keembay Display"
 	depends on DRM
 	depends on ARCH_KEEMBAY || COMPILE_TEST
 	select DRM_KMS_HELPER