ARM: dts: beagle-x15-common: Model 5V0 regulator

On am57xx-beagle-x15, 5V0 is connected to P16, P17, P18 and P19
connectors. On am57xx-evm, 5V0 regulator is used to get 3V6 regulator
which is connected to the COMQ port. Model 5V0 regulator here in order
for it to be used in am57xx-evm to model 3V6 regulator.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>