If U-Boot is located on MMC, SPL and U-Boot proper are glued together.
More precisely, SPL is stored 4 times. Take this and its padding into
account and adjust sector number via board_spl_mmc_get_uboot_raw_sector.
This allows loading from a partition, without the need to hard-code the
offset via SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Tien Fong Chee <tien.fong.chee@altera.com>