ARM: dts: keystone-k2g: Move ti,non-removable property to board dts

On 66AK2G EVM mmc1 is connected to emmc whereas 66AK2G ICE baord has SD
card slot connected to mmc1. Therefore move emmc specific
ti,non-removable property from SoC file to EVM's dts file.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>