x86/CPU/AMD: Disable INVLPGB on Zen2

AMD Cyan Skillfish (Family 17h, Model 47h, Stepping 0h) has an issue
that causes system oopses and panics when performing TLB flush using
INVLPGB.

However, the problem is that that machine has misconfigured CPUID and
should not report the INVLPGB bit in the first place. So zap the
kernel's representation of the flag so that nothing gets confused.

  [ bp: Massage. ]

Fixes: 767ae437 ("x86/mm: Add INVLPGB feature and Kconfig entry")
Signed-off-by: Mikhail Paulyshka <me@mixaill.net>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/1ebe845b-322b-4929-9093-b41074e9e939@mixaill.net