KVM: x86: remove redundant ret variable

Return value from apic_get_tmcct() directly instead of taking
this in another redundant variable.

Signed-off-by: zhang songyi <zhang.songyi@zte.com.cn>
Link: https://lore.kernel.org/r/202211231704457807160@zte.com.cn


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