drm/virtio: kconfig: Fixup white space.

Use tabs instead of spaces.
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1475913318-12275-1-git-send-email-peter.griffin@linaro.org
Link: http://patchwork.freedesktop.org/patch/msgid/1476238699-25820-1-git-send-email-jiang.biao2@zte.com.cn

drivers/gpu/drm/virtio/Kconfig

 config DRM_VIRTIO_GPU
 	tristate "Virtio GPU driver"
 	depends on DRM && VIRTIO
-        select DRM_KMS_HELPER
-        select DRM_TTM
+	select DRM_KMS_HELPER
+	select DRM_TTM
 	help
 	   This is the virtual GPU driver for virtio.  It can be used with
-           QEMU based VMMs (like KVM or Xen).
+	   QEMU based VMMs (like KVM or Xen).
 
 	   If unsure say M.