rxrpc: remove redundant proc_remove call

The proc_remove call is dead code as it occurs after a return and
hence can never be called. Remove it.

Detected by CoverityScan, CID#1437743 ("Logically dead code")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>