rtc: pcf85063: silence cppcheck warning

cppcheck warnings: (new ones prefixed by >>)

>> drivers/rtc/rtc-pcf85063.c:292:40: warning: Clarify calculation precedence for '&' and '?'. [clarifyCalculation]
     status = status & PCF85063_REG_SC_OS ? RTC_VL_DATA_INVALID : 0;

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211107225349.110707-1-alexandre.belloni@bootlin.com