msm: ipa: fix IPA driver processing context delete logic

During IPA driver processing context delete, a delete to
the referenced header is being done. The header deletion
will also commit the changes to H/W which includes the
processing context commit. This resulted into committing
an invalid process context as it is still in the processing
context list, but points to deleted header.
The fix is to not commit the changes when deleting the header
but only when deleting the processing context.

Change-Id: I9d3c5eec717da0b072144a1027e4582e73aaa6d9
CRs-fixed: 1044710
Signed-off-by: Ghanim Fodi <gfodi@codeaurora.org>