iommu/amd: Fix features reporting

When the AMD IOMMU doesn't have extended features, an empty line
gets issued in dmesg like so:

[    3.061417] AMD-Vi: Found IOMMU at 0000:00:00.2 cap 0x40
[    3.066757] 							<---
[    3.068294] pci 0000:00:00.2: irq 72 for MSI/MSI-X
[    3.081213] AMD-Vi: Lazy IO/TLB flushing enabled

Fix it.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>