msm: pil-q6v5: Migrate to clock APIs

Rather than writing to clock controller registers directly, utilize
the clock driver and its recently-added support for LPASS and MSS
clocks needed by PIL.

Since clock hardware differences are hidden under the clock APIs,
clock control can be moved from pil-q6v5-lpass into the pil-q6v5
library and shared with other PIL drivers that will eventually use
it.

Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
Change-Id: I70d67d6abded93bcc5119e5bcec4c0211f157ac0