net/rose: remove redundant assignment to variable failed

The variable failed is being assigned a value that is never read, the
following goto statement jumps to the end of the function and variable
failed is not referenced at all.  Remove the redundant assignment.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>