defconfig: arm64: msm: enable spm-regulator and rpm-smd-regulator drivers

Enable the spm-regulator and rpm-smd-regulator drivers so that
they may be used on arm64 targets.  This will allow the Linux
kernel running on the MSM8916 application processor to send
regulator requests to the RPM.  The RPM is able to aggregate
requests from all processors in order to ensure that a minimum
sufficient state is used for regulators at any given time.  This
also allows the VDD_APC application processor supply rail to be
controlled via the SPM on MSM8916 boards.

Change-Id: I8572eba734e0f0d84b39e7f3d21db0464935555b
Signed-off-by: David Collins <collinsd@codeaurora.org>