drivers: soc: sdx_ext_ipc: Give generic name for gpios

Disassociate the driver from mdm perspective. This driver can
be reused from AP side as well. Change the gpio names applicable
in both cases.

Change-Id: Icea71d5eb3be33cfd3d461dc9bae9eda07448e74
Signed-off-by: Arun KS <arunks@codeaurora.org>