rtc: cmos: Revert "rtc: Fix the AltCentury value on AMD/Hygon platform"

There are multiple reports of this patch breaking RTC time setting for AMD
platforms.

This reverts commit 7ad295d5.

Cc: Jinke Fan <fanjinke@hygon.cn>
Link: https://lore.kernel.org/r/CABXGCsMLob0DC25JS8wwAYydnDoHBSoMh2_YLPfqm3TTvDE-Zw@mail.gmail.com
Fixes: 7ad295d5 ("rtc: Fix the AltCentury value on AMD/Hygon platform")
Link: https://lore.kernel.org/r/20200104043110.707810-1-alexandre.belloni@bootlin.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>