spl_mmc: add Falcon mode support for raw 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 sector
CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR and
CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS of kernel argument parameters
starting from sector CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR.

Signed-off-by: Peter Korsgaard <peter.korsgaard@barco.com>
diff --git a/README b/README
index c7b60e4..f371e0e 100644
--- a/README
+++ b/README
@@ -2932,6 +2932,16 @@
 		Address, size and partition on the MMC to load U-Boot from
 		when the MMC is being used in raw mode.
 
+		CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
+		Sector to load kernel uImage from when MMC is being
+		used in raw mode (for Falcon mode)
+
+		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
+		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
+		Sector and number of sectors to load kernel argument
+		parameters from when MMC is being used in raw mode
+		(for falcon mode)
+
 		CONFIG_SPL_FAT_SUPPORT
 		Support for fs/fat/libfat.o in SPL binary