msm: 8974: Remove use of Q6 MSS clocks from PIL and clock drivers

The MSS clocks needed for PIL are set to correct states upon
de-assertion of the MSS_RESTART signal used in PIL. Since access
to the MSS clock registers will eventually be locked down, and
explicit control of them is not needed anyway, remove their use
from the clock and PIL drivers.

This must be done in one commit since removing PIL usage first
wouldn't work.  The 'handoff' code in the clock driver would
disable these clocks, preventing the modem from booting.

Change-Id: Idc862544f42e3f5452482363259d4cde621ce369
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>