nb/intel/sandybridge: Use SA devid to identify PC type

Instead of using MSR IA32_PLATFORM_ID read the SystemAgent device id
to figure out the PC type. This follows the BWG which suggest to not
use MSR IA32_PLATFORM_ID for system identification.

Tested: Lenovo X220 still boots.

Change-Id: Ibddf6c75d15ca7a99758c377ed956d483abe7ec1
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78826
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/cpu/intel/model_206ax/Makefile.inc

@@ -9,10 +9,6 @@ subdirs-y += ../turbo
 
 ramstage-y += acpi.c
 
-ramstage-y += common.c
-romstage-y += common.c
-smm-y += common.c
-
 smm-y += finalize.c
 
 cpu_microcode_bins += $(wildcard 3rdparty/intel-microcode/intel-ucode/06-2a-*)

src/cpu/intel/model_206ax/common.c

@@ -1,13 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-
-#include <cpu/x86/msr.h>
-#include "model_206ax.h"
-
-int get_platform_id(void)
-{
-	msr_t msr;
-
-	msr = rdmsr(IA32_PLATFORM_ID);
-	/* Read Platform Id Bits 52:50 */
-	return (msr.hi >> 18) & 0x7;
-}

src/cpu/intel/model_206ax/model_206ax.h

@@ -131,7 +131,6 @@ void intel_model_206ax_finalize_smm(void);
 /* Configure power limits for turbo mode */
 void set_power_limits(u8 power_limit_1_time);
 int cpu_config_tdp_levels(void);
-int get_platform_id(void);
 
 static inline u8 cpu_stepping(void)
 {

src/cpu/intel/model_206ax/model_206ax_init.c

@@ -323,9 +323,6 @@ static void model_206ax_report(void)
 	fill_processor_name(processor_name);
 	printk(BIOS_INFO, "CPU: %s.\n", processor_name);
 
-	/* Print platform ID */
-	printk(BIOS_INFO, "CPU: platform id %x\n", get_platform_id());
-
 	/* CPUID and features */
 	cpu_id = cpu_get_cpuid();
 	printk(BIOS_INFO, "CPU: cpuid(1) 0x%x\n", cpu_id);