iommu/of: Remove PCI host bridge node check

of_pci_iommu_init() tries to be clever and stop its alias walk at the
device represented by master_np, in case of weird PCI topologies where
the bridge to the IOMMU and the rest of the system is not at the root.
It turns out this is a bit short-sighted, since there are plenty of
other callers of pci_for_each_dma_alias() which would also need the same
behaviour in that situation, and the only platform so far with such a
topology (Cavium ThunderX2) already solves it more generally via a PCI
quirk. As this check is effectively redundant, and returning a boolean
value as an int is a bit broken anyway, let's just get rid of it.

Reported-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Fixes: d87beb74

 ("iommu/of: Handle PCI aliases properly")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>