ARM: dts: keystone-evm: add spi nor flash support

k2hk, k2e, k2l EVM board have the same Micron N25Q128A11
SPI NOR Flash installed on SPI0 bus.

The NOR Flash is splitted on two partistions:
partition@0
	label = "u-boot-spl";
	reg = <0x0 0x80000>;
partition@1
	label = "misc";
	reg = <0x80000 0xf80000>;

Hence, add SPI NOR Flash nodes to all k2hk, k2e, k2l EVM boards.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>