spl_mmc: add Falcon mode support for FAT variant

If Falcon mode support is enabled (and the system isn't directed into
booting u-boot), it will instead try to load kernel from
CONFIG_SPL_FAT_LOAD_KERNEL_NAME file and kernel argument parameters from
CONFIG_SPL_FAT_LOAD_ARGS_NAME, both from the same partition as u-boot.

Signed-off-by: Peter Korsgaard <peter.korsgaard@barco.com>
diff --git a/README b/README
index 3780564..c7b60e4 100644
--- a/README
+++ b/README
@@ -2938,6 +2938,14 @@
 		CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
 		Filename to read to load U-Boot when reading from FAT
 
+		CONFIG_SPL_FAT_LOAD_KERNEL_NAME
+		Filename to read to load kernel uImage when reading
+		from FAT (for Falcon mode)
+
+		CONFIG_SPL_FAT_LOAD_ARGS_NAME
+		Filename to read to load kernel argument parameters
+		when reading from FAT (for Falcon mode)
+
 		CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
 		Set this for NAND SPL on PPC mpc83xx targets, so that
 		start.S waits for the rest of the SPL to load before