msm: ipa3: fix device hang issue if ipa_clk failed

if ipa-driver failed to get ipa-clk during the
device probe, seeing device hang issue due to
notifier_chain_register. The fix is to only
initialize the notifier_chain_register after
ipa-driver successfully gets ipa-clk.

Change-Id: I705bf9e2b81a9d50cda75d31504f79e082276792
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>