ARM: imx/mxs defconfigs: add MTD_SPI_NOR (new dependency for M25P80)

These defconfigs contain the CONFIG_M25P80 symbol, which is now
dependent on the MTD_SPI_NOR symbol. Add CONFIG_MTD_SPI_NOR to satisfy
the new dependency.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>