x86/rtc: Rename mach_set_rtc_mmss() to mach_set_cmos_time()

Once upon a time, before this commit in 2013:

   3195ef59 ("x86: Do full rtc synchronization with ntp")

... the mach_set_rtc_mmss() function set only the minutes and seconds
registers of the CMOS RTC - hence the '_mmss' postfix.

This is no longer true, so rename the function to mach_set_cmos_time().

[ mingo: Expanded changelog a bit. ]

Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20220813131034.768527-2-mat.jonczyk@o2.pl