msm: ipa: Remove double call for mutex_unlock

In case of an error in ipa_flt when deleting/modifying
rules, there's an uneccessary call to mutex_unlock once
commit fails.

CRs-Fixed: 681621
Change-Id: Icc147b4dd4d9bd379b76925544938c34dd443465
Acked-by: David Arinzon <darinzon@qti.qualcomm.com>
Signed-off-by: Sivan Reinstein <sivanr@codeaurora.org>