[media] mceusb: buffer parsing fixups for 1st-gen device

If we pass in an offset, we shouldn't skip 2 bytes. And the first-gen
hardware generates a constant stream of interrupts, always with two
header bytes, and if there's been no IR, with nothing else. Bail from
ir processing without calling ir_handle_raw_event when we get such a
buffer delivered to us.

Signed-off-by: Jarod Wilson <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/IR/mceusb.c

···
 		return;
 
 	/* skip meaningless 0xb1 0x60 header bytes on orig receiver */
-	if (ir->flags.microsoft_gen1 && !out)
+	if (ir->flags.microsoft_gen1 && !out && !offset)
 		skip = 2;
 
 	if (len <= skip)
···
 	/* skip meaningless 0xb1 0x60 header bytes on orig receiver */
 	if (ir->flags.microsoft_gen1)
 		i = 2;
+
+	/* if there's no data, just return now */
+	if (buf_len <= i)
+		return;
 
 	for (; i < buf_len; i++) {
 		switch (ir->parser_state) {