x86/CPUID: drop INVPCID dependency on PCID

x86/CPUID: drop INVPCID dependency on PCID

PCID validly depends on LM, as it can be enabled in Long Mode only.
INVPCID, otoh, can be used not only without PCID enabled, but also
outside of Long Mode altogether. In both cases its functionality is
simply restricted to PCID 0, which is sort of expected as no other PCID
can be activated there.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>