msm: ipa: Fix the format string vulnerability

Fix the format string vulnerability by explicitly
specifiying string argument instead of just using user-specified
string. This will prevent read/write anywhere from the stack.

CRs-Fixed: 561941

Change-Id: Idffa9a04d0f6712205ac7701c7cd7cf4a246cde0
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>