KVM: selftests: Add all known XFEATURE masks to common code

Add all known XFEATURE masks to processor.h to make them more broadly
available in KVM selftests.  Relocate and clean up the exiting AMX (XTILE)
defines in processor.h, e.g. drop the intermediate define and use BIT_ULL.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: Aaron Lewis <aaronlewis@google.com>
Tested-by: Aaron Lewis <aaronlewis@google.com>
Link: https://lore.kernel.org/r/20230405004520.421768-6-seanjc@google.com


Signed-off-by: Sean Christopherson <seanjc@google.com>