[media] media: venus: hfi_cmds: fix variable dereferenced before check

This fixes a warning found when building the driver with gcc7:

drivers/media/platform/qcom/venus/hfi_cmds.c:415
pkt_session_set_property_1x() warn: variable dereferenced before
check 'pkt' (see line 412)
drivers/media/platform/qcom/venus/hfi_cmds.c:1177
pkt_session_set_property_3xx() warn: variable dereferenced before
check 'pkt' (see line 1174)

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>