KVM: selftests: Test MONITOR and MWAIT, not just MONITOR for quirk

Fix a copy+paste error in monitor_mwait_test by switching one of the two
"monitor" instructions to  an "mwait".  The intent of the test is very
much to verify the quirk handles both MONITOR and MWAIT.

Fixes: 2325d4dd ("KVM: selftests: Add MONITOR/MWAIT quirk test")
Reported-by: Yuan Yao <yuan.yao@linux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20220711225753.1073989-2-seanjc@google.com