Remove the 'flags' variable in order to fix the following warning:

drivers/rtc/rtc-armada38x.c:91:22: warning: unused variable 'flags' [-Wunused-variable]
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>