The OMAP IOMMU driver has been adapted to the IOMMU framework
for a while now, and it does not support being built as a
module anymore. So, remove all the module references from the
OMAP IOMMU driver.
While at it, also relocate a comment around the subsys_initcall
to avoid a checkpatch strict warning about using a blank line
after function/struct/union/enum declarations.