iommu/vt-d: Remove bogus check for multi MSI-X

PCI/Multi-MSI is MSI specific and not supported for MSI-X.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Link: https://lore.kernel.org/r/20221111122013.713848846@linutronix.de