msm: rpm-regulator: Remove the hack to make RPM vreg calls no-ops on 8064

Remove the hack in rpm_vreg_set_voltage and rpm_vreg_set_frequency
which makes them no-ops for 8064.  Now that 8064 has full RPM
support, the acpuclock driver should be allowed to send regulator
requests to the RPM.

This change is a revert of the following commit after the hack was
merged into rpm-regulator.c from rpm-regulator-8960.c:
6ea0dcbf

Change-Id: I410f5a1cc45d9acbaf38c4320eeebdb2ae41652a
Signed-off-by: David Collins <collinsd@codeaurora.org>