arm: socfpga: Fix "improve raw MMC SPL boot"

This fixes commit d31e9c57 ,
which broke booting from SD card on all SoCFPGA boards. The
patch assumes the bootloader partition to be partition 3, at
the end of the SD card, which doesn't make any sense. U-Boot
assumes the bootloader partition is partition 1 or that the
bootloader image is at offset +1 MiB from the start of SD card.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Sylvain Lesne <lesne@alse-fr.com>

include/configs/socfpga_common.h

@@ -346,7 +346,7 @@ unsigned int cm_get_qspi_controller_clk_hz(void);
 #define CONFIG_SPL_FS_LOAD_PAYLOAD_NAME		"u-boot-dtb.img"
 #define CONFIG_SPL_LIBDISK_SUPPORT
 #else
-#define CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION	3
+#define CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION	1
 #define CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR	0x200 /* offset 512 sect (256k) */
 #define CONFIG_SPL_LIBDISK_SUPPORT
 #endif