msm: ipa: fix boot crash

dma_free_coherent cannot be called from interrupt context.
This is enforced on arm64 platform. Change the locking scope
to satisfy this requirement.

Change-Id: I6cd6b152686a90c8b9a748d8abba187420919f07
Signed-off-by: Ravi Gummadidala <rgummadi@codeaurora.org>