configs: sama5d2_xplained: fix bootcmd/args for spi+emmc demo

For sama5d2_xplained_spiflash_defconfig, we have the demo layout
as presented on this link:
http://www.at91.com/linux4sam/bin/view/Linux4SAM/Sama5d2XplainedMainPage#SPI_eMMC_Flash_demo_Memory_map

on SPI Flash (4 Mbyte) we have Bootstrap (second level bootloader), U-boot + env

and kernel+dtb we keep on eMMC on single partition in /boot directory, formatted
with ext4.

Thus, changing the boot command to reflect this demo for the spiflash config,
and fixing up bootargs. Sama5d2_xplained does not have NAND flash, so the
bootargs were completely wrong.

Fixes: "5abc1a45": common: Move CONFIG_BOOTARGS to Kconfig
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
diff --git a/configs/sama5d2_xplained_spiflash_defconfig b/configs/sama5d2_xplained_spiflash_defconfig
index f4333ea..92da120 100644
--- a/configs/sama5d2_xplained_spiflash_defconfig
+++ b/configs/sama5d2_xplained_spiflash_defconfig
@@ -18,7 +18,7 @@
 CONFIG_SPI_BOOT=y
 CONFIG_BOOTDELAY=3
 CONFIG_USE_BOOTARGS=y
-CONFIG_BOOTARGS="console=ttyS0,115200 earlyprintk mtdparts=atmel_nand:256k(bootstrap)ro,512k(uboot)ro,256K(env),256k(env_redundant),256k(spare),512k(dtb),6M(kernel)ro,-(rootfs) rootfstype=ubifs ubi.mtd=7 root=ubi0:rootfs"
+CONFIG_BOOTARGS="console=ttyS0,115200 earlyprintk root=/dev/mmcblk0p1 rw rootwait"
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_SPL_SPI_LOAD=y
 CONFIG_HUSH_PARSER=y