gpu: ipu-v3: add support for 15-bit RGB with 1-bit alpha formats

This patch adds support for ARGB1555, ABGR1555, RGBA5551, and BGRA5551
in-memory formats.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
diff --git a/drivers/gpu/ipu-v3/ipu-common.c b/drivers/gpu/ipu-v3/ipu-common.c
index e5a38d2..c0b1916 100644
--- a/drivers/gpu/ipu-v3/ipu-common.c
+++ b/drivers/gpu/ipu-v3/ipu-common.c
@@ -57,6 +57,10 @@
 enum ipu_color_space ipu_drm_fourcc_to_colorspace(u32 drm_fourcc)
 {
 	switch (drm_fourcc) {
+	case DRM_FORMAT_ARGB1555:
+	case DRM_FORMAT_ABGR1555:
+	case DRM_FORMAT_RGBA5551:
+	case DRM_FORMAT_BGRA5551:
 	case DRM_FORMAT_RGB565:
 	case DRM_FORMAT_BGR565:
 	case DRM_FORMAT_RGB888: