rtc: pl031: fix rtc features null pointer dereference

rtc: pl031: fix rtc features null pointer dereference

commit ea6af39f3da50c86367a71eb3cc674ade3ed244c upstream.

When there is no interrupt line, rtc alarm feature is disabled.

The clearing of the alarm feature bit was being done prior to allocations
of ldata->rtc device, resulting in a null pointer dereference.

Clear RTC_FEATURE_ALARM after the rtc device is allocated.

Fixes: d9b0dd54a194 ("rtc: pl031: use RTC_FEATURE_ALARM")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Pouladi <quic_apouladi@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220225161924.274141-1-quic_eberman@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>