msm: ipa3: Fix to NULL terminate the header pointer in proc header table

While resetting the header rules if it find invalid header ID it
will return before freeting proc header table it was leading to use
after free when accessing the header pointer from proc header table.
Adding changes to NULL terminating header pointer in proc header table
after header table deleted from the list.

Change-Id: If270d855d3907e61368336316161a250053e1e62
Signed-off-by: Ashok Vuyyuru <avuyyuru@codeaurora.org>