iommu/amd: Do not loop forever when trying to increase address space

When increase_address_space() fails to allocate memory, alloc_pte()
will call it again until it succeeds. Do not loop forever while trying
to increase the address space and just return an error instead.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Tested-by: Qian Cai <cai@lca.pw>
Link: https://lore.kernel.org/r/20200504125413.16798-3-joro@8bytes.org


Signed-off-by: Joerg Roedel <jroedel@suse.de>