ARM: gic: Remove ARCH_MSM8625 around the gic_save APIs

msm_gic_save/restore APIs were added to save the context of the
GIC across the apps. power collapse since 8625 PM framework
doesn't use the CPUIdle framework of the kernel. If the CPUIdle
framework was in use then we could have used the GIC driver provided
notification mechanism which takes of calling appropriate functions.
There is no need to protect these APIs using this #ifdef since there
is nothing specific to 8625 inside, also add empty functions for save
and restore since not all targets have CPU_PM defined.

Change-Id: I02bb4e4021c31caf7ab1282fb675d45ffba42a66
Signed-off-by: Trilok Soni <tsoni@codeaurora.org>