Add register definitions for W83627HF based on publicly available

Add register definitions for W83627HF based on publicly available
specification and local testing.

Also tweak a little bit algorithm for (internal) device ID calculation:
Chips from the W83627HF/F/HG/G family have an ID of 0x52 and a multitude of
revisions (0x1x, 0x3a, 0x41, maybe more), chips from the W83627HF/GF family
have the same device ID but revisions 0xfx.

Please note that the last line of the patch simply fixes the comment
about internal device ID composition (upper half of reg 0x21 is used).
I chose the most conservative way of detecting W83627HF - only if reg
0x21 value matches 0xFx we skip the previous logic and keep using it for
all other revisions.

Signed-off-by: Andriy Gapon <avg@icyb.net.ua>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3670 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1