AMD K8 fam10: Refactor Kconfig SB_HT_CHAIN_ON_BUS0

If SB_HT_CHAIN_ON_BUS0 is selected, HyperTransport chain for System Bus
is the first to scan and it will be assigned with bus number 0.

If HT_CHAIN_DISTRIBUTE is selected, each link will reserve a fixed range
of bus numbers instead of assigning consecutive numbers across all the links.

All fam10 have SB_HT_CHAIN_ON_BUS0 selected under northbridge.
Follow-up can easily drop this if we find this is dictated by architecture.

Change-Id: I8deddcb4c3fd679b6b27e2879d9dba3895c4dd6f
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/8366
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <edward.ocallaghan@koparo.com>
Reviewed-by: Timothy Pearson <tpearson@raptorengineeringinc.com>

src/mainboard/iei/kino-780am2-fam10/Kconfig

@@ -40,10 +40,6 @@ config MAX_PHYSICAL_CPUS
 	int
 	default 2
 
-config SB_HT_CHAIN_ON_BUS0
-	int
-	default 1
-
 config HT_CHAIN_END_UNITID_BASE
 	hex
 	default 0x1