Sort the files in the am355x directory.
Don't confuse frontend with zero length data moves, just return immediately.

MFC after:	1 week
Remove the need for files.beaglebone and std.beaglebone by moving the one
option they defined into files.am335x.
Fix most of the warnings in kdump(1).

Sponsored by:	Norse
Remove ti_mmchs.c, it has been replaced by ti_sdhci.c.