iommu/vt-d: Remove a useless BUG_ON(dev->is_virtfn)

When dmar_alloc_pci_notify_info() is being invoked, the invoker has
ensured the dev->is_virtfn is false. So, remove the useless BUG_ON in
dmar_alloc_pci_notify_info().

Signed-off-by: Tina Zhang <tina.zhang@intel.com>
Link: https://lore.kernel.org/r/20230406065944.2773296-7-tina.zhang@intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel/dmar.c

@@ -127,8 +127,6 @@ dmar_alloc_pci_notify_info(struct pci_dev *dev, unsigned long event)
 	struct pci_dev *tmp;
 	struct dmar_pci_notify_info *info;
 
-	BUG_ON(dev->is_virtfn);
-
 	/*
 	 * Ignore devices that have a domain number higher than what can
 	 * be looked up in DMAR, e.g. VMD subdevices with domain 0x10000