rtc_qmsi: Call QMSI 1.4 context save/restore functions.

This commit removes the RTC interrupt masking/unmasking needed after
wake up as that functionality is now available in QMSI 1.4. The QMSI
save/restore functions are called instead.

Change-Id: I15b5063fa64c71b125edd2c709410b5ae655032e
Signed-off-by: Juan Solano <juanx.solano.menacho@intel.com>