splash: Skip the RGB555 mode

Current JPEG decoding uses the RGB888 or RGB565. So we need to skip
RGB555 mode.

Signed-off-by: Zheng Bao <fishbaozi@gmail.com>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
diff --git a/src/bootsplash.c b/src/bootsplash.c
index c572685..165c98d 100644
--- a/src/bootsplash.c
+++ b/src/bootsplash.c
@@ -81,7 +81,8 @@
             continue;
         u8 depth = mode_info->bits_per_pixel;
         if (bpp_req == 0) {
-            if (depth != 16 && depth != 24 && depth != 32)
+            if ((depth != 16 && depth != 24 && depth != 32)
+                || mode_info->green_size == 5)
                 continue;
         } else {
             if (depth != bpp_req)