kernel: Move some IOMMU options to generic

kernel: Move some IOMMU options to generic

This adds some missing IOMMU related options for x86/64 and moves some
of them to generic for all targets.

On x86 IOMMU_DEFAULT_DMA_LAZY is used by default, on all other platforms
IOMMU_DEFAULT_DMA_STRICT is the default. we just follow the default
kernel configuration here.

Fixes: 8fea4a102ccd ("x86/64: enable IOMMU support")
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>