configs: k2g_evm: Add TI power processor support

Enable support for PMMC the TI power processor on K2G. This processor
manages all power management related activities on the SoC and and
allows the Operating Systems on compute processors such as ARM, DSP to
offload the power logic away into the power processor.

Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>