wcnss: Remove enabling of CXO in suspend/resume

CXO was explicitly turned ON before writing into PMU registers, this
is not required now. WLAN driver will only send suspend/resume
notifications to WCNSS when it's is BMPS mode. And in this mode, Apps
can always access PMU register.

Change-Id: I6a2e59b541ecea16be9e9463f26add6b23d4bdb0
Signed-off-by: Sameer Thalappil <sameert@codeaurora.org>