Change in coreboot[master]: soc/amd: add and use fch_enable_hpet_decode

[Felix Held (Code Review)]

Attention is currently required from: Jason Glenesk, Raul Rangel.
Felix Held has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/50512 )

Change subject: soc/amd: add and use fch_enable_hpet_decode
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Patch Set 3:

(2 comments)

File src/soc/amd/common/block/acpimmio/mmio_util.c:

https://review.coreboot.org/c/coreboot/+/50512/comment/5e8bd505_a8f31b92 
PS2, Line 79: HPET_FED0_EN
> those are the default values after reset. […]

Done

File src/soc/amd/common/block/include/amdblocks/acpimmio.h:

https://review.coreboot.org/c/coreboot/+/50512/comment/cecaadbd_53577fdf 
PS2, Line 20: FED0
> yes, there are two possible mappings for the hpet and the usual one that we'll be  using and announc […]

removed that and added a comment instead