video: Allow drivers to allocate the frame buffer themselves

When plat->base is set by driver then skip frame buffer reservation
and allocation.

Signed-off-by: Pali Rohár <pali@kernel.org>
diff --git a/drivers/video/video-uclass.c b/drivers/video/video-uclass.c
index 7d499bc..88797d4 100644
--- a/drivers/video/video-uclass.c
+++ b/drivers/video/video-uclass.c
@@ -33,7 +33,8 @@
  * information represents the requires size and alignment of the frame buffer
  * for the device. The values can be an over-estimate but cannot be too
  * small. The actual values will be suppled (in the same manner) by the bind()
- * method after relocation.
+ * method after relocation. Additionally driver can allocate frame buffer
+ * itself by setting plat->base.
  *
  * This information is then picked up by video_reserve() which works out how
  * much memory is needed for all devices. This is allocated between
@@ -78,6 +79,10 @@
 	if (!plat->size)
 		return 0;
 
+	/* Allow drivers to allocate the frame buffer themselves */
+	if (plat->base)
+		return 0;
+
 	align = plat->align ? plat->align : 1 << 20;
 	base = *addrp - plat->size;
 	base &= ~(align - 1);