soc/amd/glinda: introduce and use pstate_msr bitfield struct

soc/amd/glinda: introduce and use pstate_msr bitfield struct

Add the pstate_msr union of a bitfield struct and a raw uint64_t to
allow easier access of the bitfields of the P state MSRs which will be
implemented in a following patch. PPR #57254 Rev 1.52 was used as a
reference. This patch adds and uses the cpu_vid_8 bit which is the 9th
bit of the voltage ID specified in the SVI3 spec. The way the CPU
frequency is encoded in the PSTATE MSR has changed compared to Phoenix,
so also update the comment in the SoC's Kconfig file that the selected
SOC_AMD_COMMON_BLOCK_TSC_FAM17H_19H is likely incompatible which will be
addressed in the future.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I3d1878ce4d9bc62ac597e6f71ef9630491628698
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73924
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Fred Reitberger <reitbergerfred@gmail.com>