clk: mediatek: add mt7986 clock support

clk: mediatek: add mt7986 clock support

Add MT7986 clock support, include topckgen, apmixedsys,
infracfg, and ethernet subsystem clocks.

Signed-off-by: Sam Shih <sam.shih@mediatek.com>
Link: https://lore.kernel.org/r/20211217121148.6753-4-sam.shih@mediatek.com
Reviewed-by: Ryder Lee <ryder.lee@kernel.org>
[sboyd@kernel.org: Fix typos in Kconfig, there are more existing typos
from where they were copied from of but whatever]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>