pmap_mapdev: Consistently use vm_paddr_t for the first argument.

[jhb]

Summary

The devmap variants used vm_offset_t for some reason, and a few places
explicitly cast bus addresses to vm_offset_t. (Probably those casts
along with similar casts for vm_size_t should just be removed and
instead permit the compiler to DTRT.)

Sponsored by: DARPA

[jhb]

sys/kern/subr_devmap.c

273

This can probably be reverted back to trunc_page? I think I was just overly cautious.

293

It might be a nice followup if pmap_mapdev() on aarch64 and risc-v just called pmap_mapdev_attr() so we could avoid code duplication.

[markj]

sys/kern/subr_devmap.c

273

I can't see any reason not to use trunc_page() with a vm_paddr_t...