msm: krait-regulator: switch mode on the same cpu

The driver currently runs LDO-BHS mode switches while possibly
running on a different CPU. The CPU for which the mode switch is
issued could be running its SPM sequence as a part of going in or
coming out of power collapse. The LDO-BHS switching executed from a
different CPU could race with the mode switches done in SPM sequence
leaving the CPU in a bad state.

Fix this by executing LDO-BHS mode switches on the target CPU. This
guarantees that the SPM sequence won't be running on that CPU while
changing modes.

CRs-Fixed: 523449
Change-Id: I863ce3bcd6dd9ba3155c4573071f01e7a020ef48
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>