msm: ipa: Fix to accessing ipa_q6_clnt handle

There is a possibility that ipa_q6_clnt handle is used
after it is freed espcially in scenarios where the handle
is freed on service exited notification. Make a change to
not clean up the handle when service is exited instead
do it as part of BEFORE_POWERUP processing only.

Change-Id: I789cdec6f056b17a605f3454e6cd5702542c454f
Acked-by: Chaitanya Pratapa <cpratapa@qti.qualcomm.com>
Signed-off-by: Sridhar Ancha <sancha@codeaurora.org>