Revision 2776

More range for HT_CHAIN_UNITID_BASE and HT_CHAIN_END_UNITID_BASE.

For example: in C51/MCP55 or C51/MCP51

Will allow
1. C51 at 0x10 to 0x14, and MCP at 0 to 4
2. C51 at 1 to 4, and MCP at 7 to 0x0a

The reason is c51/mcp51/mcp55 reported unitid is 0x0f (far beyond it
needed), and will prevent us from putting them on bus 0.

Typical values for c51/mcp55 or c51/mcp51:
HT_CHAIN_UNITID_BASE = 0x10 # for C51
HT_CHAIN_END_UNITID_BASE = 0 # for mcp

If only have mcp with c51, 
HT_CHAIN_UNITID_BASE = 0 # for MCP
#HT_CHAIN_END_UNITID_BASE = 0 # default value 0x20

Signed-off-by: Yinghai Lu <yinghai.lu@amd.com>
Acked-by: Stefan Reinauer <stepan@coresystems.de>