msm: acpuclock-krait: Disable secondary clock source gating during switches

To workaround a Krait errata on 8064, disable secondary clock source
gating during the MUX switch. This errata was already worked around
in msm-krait-l2-accessors.c in a different way, but that will soon
be removed in favor of this and some power-collapse changes.

Signed-off-by: Matt Wagantall <mattw@codeaurora.org>

Change-Id: Iffe42ee7216c9b9c4a4e68ddfe80fbc03b0413b0
Signed-off-by: Neha Pandey <nehap@codeaurora.org>