msm_serial_hs: Manage clock path-vote correctly

clock path vote is needed for core and iface vote,
so remove it after these votes are removed, and
make sure clock path vote/unvote are balanced by
removing unnecessary clock path vote

CRs-Fixed: 606403
Change-Id: I2ca2ef1cac3f0aacb7d21eb4da8bed3d39e0158c
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>