x86/hyper-v: Fix wrong merge conflict resolution

When the mapping betwween the Linux notion of CPU ID to the hypervisor's
notion of CPU ID is not initialized, IPI must fall back to the
non-enlightened path.

The recent merge of upstream changes into the hyperv branch resolved a
merge conflict wronly by returning success in that case, which results in
the IPI not being sent at all. Fix it up.

Fixes: 8f63e9230d ("Merge branch 'x86/urgent' into x86/hyperv")
Reported-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: gregkh@linuxfoundation.org
Cc: devel@linuxdriverproject.org
Cc: olaf@aepfle.de
Cc: apw@canonical.com
Cc: jasowang@redhat.com
Cc: hpa@zytor.com
Cc: sthemmin@microsoft.com
Cc: Michael.H.Kelley@microsoft.com
Cc: vkuznets@redhat.com
Link: https://lkml.kernel.org/r/20180720035009.3995-1-kys@linuxonhyperv.com

arch/x86/hyperv/hv_apic.c

@@ -168,7 +168,7 @@ static bool __send_ipi_mask(const struct cpumask *mask, int vector)
 	for_each_cpu(cur_cpu, mask) {
 		vcpu = hv_cpu_number_to_vp_number(cur_cpu);
 		if (vcpu == VP_INVAL)
-			return true;
+			return false;
 
 		/*
 		 * This particular version of the IPI hypercall can