ARM: dts: keystone-k2g-evm: Add "vqmmc-supply" property for mmc0/mmc1

Add "vqmmc-supply" property for mmc0/mmc1 to indicate the supply connected
to the IO lines. Also add dt node for ldo1 regulator required for mmc1
vqmmc-supply.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>