msm: ipa3: Fix to prevent Integer Overflow

The value of `req->filter_spec_ex2_list_len`
is user input via ioctl and it's type is uint32,
so an integer overflow may occur. Which can result
in out of bound access in the following loop. Now
add changes to prevent Integer overflow.

Change-Id: Ia29b9ddc674e5dd3d5baf6623cf0a464c156d8f7
Signed-off-by: Piyush Dhyani <pdhyani@codeaurora.org>