[media] st-delta: mjpeg: fix static checker warning

Initialize 'data_offset' local variable to 0.

drivers/media/platform/sti/delta/delta-mjpeg-dec.c:415 delta_mjpeg_decode()
error: uninitialized symbol 'data_offset'.

Fixes: 433ff5b4: "[media] st-delta: add mjpeg support"
Signed-off-by: Hugues Fruchet <hugues.fruchet@st.com>
Signed-off-by: Hans Verkuil <hansverk@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/sti/delta/delta-mjpeg-dec.c

@@ -375,7 +375,7 @@ static int delta_mjpeg_decode(struct delta_ctx *pctx, struct delta_au *pau)
 	struct delta_mjpeg_ctx *ctx = to_ctx(pctx);
 	int ret;
 	struct delta_au au = *pau;
-	unsigned int data_offset;
+	unsigned int data_offset = 0;
 	struct mjpeg_header *header = &ctx->header_struct;
 
 	if (!ctx->header) {