revert 4GB workarounds for bge and aac

[tychon]

Summary

After r346386, DMA transactions may again cross 4GB boundaries. I had intended to return the per-device workaround for devices known to have 64-bit issues. Apparently while I got the header file component I missed the salient change to bge in the shuffle. Also add the necessary workaround for aac.

This is a straightforward revert of r232766 and r232260 respectively.

[kib]

sys/dev/aac/aac_pci.c

447

aac uses BUS_SPACE_MAXSIZE_32BIT in other places.

[tychon]

sys/dev/aac/aac_pci.c

447

Yeah, I see that but BUS_SPACE_MAXSIZE_32BIT (0xFFFFFFFF) isn't a power-of-2. Isn't that a requirement for alignment?

[kib]

sys/dev/aac/aac_pci.c

447

I see.