Since we support PKU for HVM guests, the respective insns should also be
recognized by the emulator.
In emul_test_read_cr() instead of further extending the comment to
explain the hex numbers, switch to using X86_CR4_* values.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>