splash_source: add support for filesystem formatted mmc

Add support for loading splash image from an SD card formatted with
a filesystem. Update boards to maintain original behavior where needed.

Cc: Igor Grinberg <grinberg@compulab.co.il>
Cc: Tom Rini <trini@konsulko.com>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
diff --git a/board/compulab/cm_t35/cm_t35.c b/board/compulab/cm_t35/cm_t35.c
index ccefc40..189d903 100644
--- a/board/compulab/cm_t35/cm_t35.c
+++ b/board/compulab/cm_t35/cm_t35.c
@@ -64,6 +64,7 @@
 	{
 		.name = "nand",
 		.storage = SPLASH_STORAGE_NAND,
+		.flags = SPLASH_STORAGE_RAW,
 		.offset = 0x100000,
 	},
 };