kernel: alarm: Do not call rtc_alarm_irq_enable in IRQ Disabled context

Currently shutdown hook of alarm driver is calling
the rtc_alarm_irq_enable API in interrupts disabled
context. So fix the alarm_shutdown function to call
in API rtc_alarm_irq_enable in interrupt enabled context.

CRs-Fixed: 591790
Change-Id: Iebd82482be1dc95c6c978b617e1c18eb36e1b6eb
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
board-8064-pmic: enable rtc_alarm_powerup

Change-Id: I7a54ce234cf7b8d208509ea8bb83ad49723553f9