x86/cpu: Fix the AMD Fam 17h, Fam 19h, Zen2 and Zen4 MSR enumerations

The comments introduced in <asm/msr-index.h> in the merge conflict fixup in:

  8f4156d5 ("Merge branch 'x86/urgent' into perf/core, to resolve conflict")

... aren't right: AMD naming schemes are more complex than implied,
family 0x17 is Zen1 and 2, family 0x19 is spread around Zen 3 and 4.

So there's indeed four separate MSR namespaces for:

  MSR_F17H_
  MSR_F19H_
  MSR_ZEN2_
  MSR_ZEN4_

... and the namespaces cannot be merged.

Fix it up. No change in functionality.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/D99589F4-BC5D-430B-87B2-72C20370CF57@exactcode.com