8974: liquid: add atheros gpio configs only for liquid

This change adds required gpiomux active and suspend
configurations to support AR3002 low power mode only on
liquid platform.

Change-Id: I49035fefa2c77333c2ff3ed39cc325d9d75edd19
Signed-off-by: Ram Mohan Korukonda <rkorukon@codeaurora.org>