drivers/rtc/rtc-efi.c: avoid subtracting day twice when computing year days
Compared source code of rtc-lib.c::rtc_year_days() with
efirtc.c::rtc_year_days(), found the code in rtc-efi decreases value of
day twice when it computing year days. rtc-lib.c::rtc_year_days() has
already decrease days and return the year days from 0 to 365.