msm: footswitch-8x60: Update collapse steps for memory retention robustness

Disabling clocks before collapsing power to the core is recommended
since halting clock results in memory periphery power collapse. If
that happens right after collapsing the core's power, there is a
theoretical possibility that an unwanted state may be latched into
memory.

Since memory retention is not assumed across a collapse, this
should not be a problem anyway. Still, change this now so it doesn't
get forgotten and cause problems in the future should memory
retention be used.

Change-Id: Ie9c7bb0b8096e0e23fb8d0312982e5ea5eccacc6
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>