soc/amd/common/cpu/tsc: add get_pstate_core_freq for family 15h and 16h

This function will be used in follow-up patches for both the TSC rate
calculation and the still to be implemented P state ACPI table
generation in coreboot. The was checked against BKDG 52740 Rev 3.05,
BKDG #55072 Rev 3.04, and BKDG #50742 Rev 3.08.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I9afaa044da994d330c3e546b774eb1f82e4f30e4
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74011
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>

src/soc/amd/stoneyridge/Kconfig

@@ -26,6 +26,7 @@ config SOC_AMD_STONEYRIDGE
 	select SOC_AMD_COMMON_BLOCK_AOAC
 	select SOC_AMD_COMMON_BLOCK_BANKED_GPIOS
 	select SOC_AMD_COMMON_BLOCK_CAR
+	select SOC_AMD_COMMON_BLOCK_CPUFREQ_FAM15H_16H
 	select SOC_AMD_COMMON_BLOCK_HDA
 	select SOC_AMD_COMMON_BLOCK_I2C
 	select SOC_AMD_COMMON_BLOCK_IOMMU