Drop config variable CPU_MODEL_INDEX

It's only used in the ACPI generator for Sandybridge/Ivybridge CPUs
and the code can easily be changed to not rely on any Kconfig magic.

Change-Id: Ie2f92edfe8908f7eb2fda3088f77ad22f491ddcf
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/1047
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

src/cpu/intel/model_206ax/Kconfig

@@ -36,18 +36,10 @@ if CPU_INTEL_MODEL_206AX
    config CPU_MODEL_NAME
 	string
 	default "Intel SandyBridge CPU"
-
-   config CPU_MODEL_INDEX
-	hex
-	default 0x2a
 endif
 
 if CPU_INTEL_MODEL_306AX
    config CPU_MODEL_NAME
 	string
 	default "Intel IvyBridge CPU"
-
-   config CPU_MODEL_INDEX
-	hex
-	default 0x3a
 endif