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

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

drivers/media/platform/qcom/venus/helpers.c:157
load_per_instance() warn: variable dereferenced before check
'inst' (see line 153)
Signed-off-by: NStanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/qcom/venus/helpers.c

@@ -150,14 +150,12 @@ static int intbufs_free(struct venus_inst *inst)
 
 static u32 load_per_instance(struct venus_inst *inst)
 {
-	u32 w = inst->width;
-	u32 h = inst->height;
 	u32 mbs;
 
 	if (!inst || !(inst->state >= INST_INIT && inst->state < INST_STOP))
 		return 0;
 
-	mbs = (ALIGN(w, 16) / 16) * (ALIGN(h, 16) / 16);
+	mbs = (ALIGN(inst->width, 16) / 16) * (ALIGN(inst->height, 16) / 16);
 
 	return mbs * inst->fps;
 }