nci_uart_register returns -EINVAL immediately when nu->ops.recv is not
set. So the same 'if' later never triggers so nci_uart_default_recv is
never used. Drop it.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210302062214.29627-17-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>