svm: Fix AVIC incomplete IPI emulation

[ Upstream commit bb218fbcfaaa3b115d4cd7a43c0ca164f3a96e57 ]

In case of incomplete IPI with invalid interrupt type, the current
SVM driver does not properly emulate the IPI, and fails to boot
FreeBSD guests with multiple vcpus when enabling AVIC.

Fix this by update APIC ICR high/low registers, which also
emulate sending the IPI.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>