ARM: multi_v7_defconfig: Enable CONFIG_MTD_CFI_AMDSTD and CONFIG_MTD_PHYSMAP_OF.

Enable CONFIG_MTD_CFI_AMDSTD to support CFI command set 0002.
Enable CONFIG_MTD_PHYSMAP_OF which allows the NOR flash driver code to
communicate with chips which are mapped physically into the CPU's memory.

[ Leo: CONFIG_MTD_PHYSMAP_OF implied ]

Signed-off-by: Pankit Garg <pankit.garg@nxp.com>