soc/intel/broadwell: Use Haswell CPU headers

Now that the boards use Haswell's CPU code, Broadwell can be updated.

Change-Id: If07e5272f07edb59bb18eef1f80d7d5807b26e66
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46949
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/cpu/intel/haswell/haswell.h

@@ -168,12 +168,19 @@ void intel_cpu_haswell_finalize_smm(void);
 void set_power_limits(u8 power_limit_1_time);
 int cpu_config_tdp_levels(void);
 
+void set_max_freq(void);
+
 /* CPU identification */
 static inline u32 cpu_family_model(void)
 {
 	return cpuid_eax(1) & 0x0fff0ff0;
 }
 
+static inline u32 cpu_stepping(void)
+{
+	return cpuid_eax(1) & 0xf;
+}
+
 static inline int haswell_is_ult(void)
 {
 	return CONFIG(INTEL_LYNXPOINT_LP);