util/superiotool: add support for Nuvoton NCT6796D
Registers and default values taken from public datasheet:
https://www.nuvoton.com/resource-files/NCT6796D_Datasheet_V0_6.pdf
TEST=build/dump SIO registers on Erying SRMJ4 mainboard
Change-Id: I0ff940a17b0c38a5ca66e90dd4e075a2b04dcfc1
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/80003
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>