board: ti: DRA7: Add DRA72-rev C evm pinmux

Add the pinmux data for rev C evm. This is different from previous
revisions of the platform thanks to the deltas introduced both from
silicon side and from SoC side.

Based on J6EcoES2_EVM_Base_Config-20160309b and PCT-DRA72x-v1.3.0.7 for
SR2.0 silicon.

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