rtc: omap: fix error path when pinctrl_register fails

commit 26e480f7bb7840fc0daa9c3af7c4501b2cf5902f upstream.

If pinctrl_register() fails probe will return with an error without locking
the RTC and disabling pm_runtime.
Set ret and jump to err instead.

Fixes: 97ea1906 ("rtc: omap: Support ext_wakeup configuration")
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>