sp5100_tco: fix the device check for SB800 and later chipsets

For SB800 and later chipsets, the register definitions are the same
with SB800. And for SB700 and older chipsets, the definitions should
be same with SP5100/SB7x0.

Signed-off-by: Huang Rui <ray.huang@amd.com>
Cc: Denis Turischev <denis.turischev@compulab.co.il>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>