msm: ipa: typo in ioctl ipa3_ioctl_mdfy_flt_rule_v2 function

Fixes the typo while type casting the kernel pointer.

Change-Id: Ie8e1128b2edf6cb2b1aff71ddaf0fdee286737c5
Acked-by: Suhas Mallesh <smallesh@qti.qualcomm.com>
Signed-off-by: Michael Adisumarta <madisuma@codeaurora.org>