thunderbolt: Add casts to prevent endianness warnings

Thunderbolt packets are big endian. Cast pkg->buffer to __be32* when
accessing the checksum.

Reported-by: kbuild test robot <[e-mail]>
Signed-off-by: Andreas Noever <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/thunderbolt/ctl.c

···
 	pkg->frame.sof = type;
 	pkg->frame.eof = type;
 	cpu_to_be32_array(pkg->buffer, data, len / 4);
-	*(u32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
+	*(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
 
 	res = ring_tx(ctl->tx, &pkg->frame);
 	if (res) /* ring is stopped */
···
 	}
 
 	frame->size -= 4; /* remove checksum */
-	if (*(u32 *) (pkg->buffer + frame->size)
+	if (*(__be32 *) (pkg->buffer + frame->size)
 			!= tb_crc(pkg->buffer, frame->size)) {
 		tb_ctl_err(pkg->ctl,
 			   "RX: checksum mismatch, dropping packet\n");