configs: imxrt1050-evk: enable D/I cache

Soc supports cache so let's enable it.

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>

configs/imxrt1050-evk_defconfig

 CONFIG_ARM=y
-CONFIG_SYS_ICACHE_OFF=y
-CONFIG_SYS_DCACHE_OFF=y
 CONFIG_ARCH_IMXRT=y
 CONFIG_SYS_TEXT_BASE=0x80002000
 CONFIG_SPL_GPIO_SUPPORT=y