net/9p: set error to EREMOTEIO if trans->write returns zero

If trans->write returns 0, p9_write_work goes through the error path, but
sets the error code to zero.

This patch sets the error code to EREMOTEIO if trans->write returns zero
value.

Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>
1 file changed