x86/cpu/topology: Consolidate AMD and Hygon cases in parse_topology()

x86/cpu/topology: Consolidate AMD and Hygon cases in parse_topology()

Merge the two separate switch cases for AMD and Hygon as they share the
common cpu_parse_topology_amd().

Also drop the IS_ENABLED(CONFIG_CPU_SUP_AMD/HYGON) guards, because
1) they are dead code: when a vendor's CONFIG_CPU_SUP_* is disabled, its
   vendor detection code (in amd.c / hygon.c) is not compiled, so
   x86_vendor will never be set to X86_VENDOR_AMD / X86_VENDOR_HYGON,
   instead it will default to X86_VENDOR_UNKNOWN and those switch cases
   are unreachable.
2) topology_amd.o is always built (obj-y), so cpu_parse_topology_amd() is
   always available regardless of CPU_SUP_* configuration.

Signed-off-by: Wei Wang <wei.w.wang@hotmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Yongwei Xu <xuyongwei@open-hieco.net>
Link: https://patch.msgid.link/SI2PR01MB4393D6B7E17AB05612AEE925DC4BA@SI2PR01MB4393.apcprd01.prod.exchangelabs.com