qcom: smcinvoke: Fix stack overflow for arr_filp

arr_filp is an alias to filp_to_release. It is exposed
to access indices greater than allotted space of 15 bytes,
equal to size of OBJECT_COUNTS_MAX_OO. This change fixes
the stack overflow by taking an independent variable to track
the number of output objects.

Change-Id: Idca9cef3c69693d27d4ca3d0e0b4845fc27c998a
Signed-off-by: Anmolpreet Kaur <anmolpre@codeaurora.org>