rtc: omap: fix resource leak in registration error path

rtc: omap: fix resource leak in registration error path

BugLink: https://bugs.launchpad.net/bugs/1835972
commit 551757eb052986ec81cebcc6301cc1c4f8dca938 upstream.

Make sure to deregister the pin controller in case rtc registration
fails.

Fixes: 57072758623f ("rtc: omap: switch to rtc_register_device")
Cc: stable <stable@vger.kernel.org>     # 4.14
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>