intel: Use MSR_EBC_FREQUENCY_ID instead of 0x2c

Change-Id: Ib1b761fc417f1bb000f408d3bed5e8666963f51d
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/22603
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Martin Roth <martinroth@google.com>

src/include/cpu/intel/speedstep.h

@@ -40,6 +40,7 @@
 #define IA32_PERF_CTL     0x199
 #define MSR_THERM2_CTL    0x19D
 #define IA32_MISC_ENABLES 0x1A0
+#define MSR_EBC_FREQUENCY_ID	0x2c
 #define MSR_FSB_FREQ		0xcd
 #define MSR_FSB_CLOCK_VCC	0xce
 #define MSR_PMG_CST_CONFIG_CONTROL	0xe2