iommu/irq_remapping: Fix the regression of hpet irq remapping

Commit 71054d88 ("x86, hpet: Introduce x86_msi_ops.setup_hpet_msi")
introduced x86_msi_ops.setup_hpet_msi to setup hpet MSI irq
when irq remapping enabled. This caused a regression of
hpet MSI irq remapping.

Original code flow before commit 71054d88:
hpet_setup_msi_irq()
	arch_setup_hpet_msi()
		setup_hpet_msi_remapped()
			remap_ops->setup_hpet_msi()
				alloc_irte()
		msi_compose_msg()
		hpet_msi_write()
		...

Current code flow after commit 71054d88:
hpet_setup_msi_irq()
	x86_msi.setup_hpet_msi()
		setup_hpet_msi_remapped()
			intel_setup_hpet_msi()
				alloc_irte()

Currently, we only call alloc_irte() for hpet MSI, but
do not composed and wrote its msg...

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>