rpmsg: glink: Set tail pointer to 0 at end of FIFO

When wrapping around the FIFO, the remote expects the tail pointer to
be reset to 0 on the edge case where the tail equals the FIFO length.

Fixes: caf989c350e8 ("rpmsg: glink: Introduce glink smem based transport")
Cc: [e-mail]
Signed-off-by: Chris Lew <[e-mail]>
Signed-off-by: Bjorn Andersson <[e-mail]>

drivers/rpmsg/qcom_glink_smem.c

···
 	tail = le32_to_cpu(*pipe->tail);
 
 	tail += count;
-	if (tail > pipe->native.length)
+	if (tail >= pipe->native.length)
 		tail -= pipe->native.length;
 
 	*pipe->tail = cpu_to_le32(tail);