vme: move back to staging

vme: move back to staging

The VME subsystem graduated from staging into a top-level subsystem in
2012, with commit db3b9e990e75 ("Staging: VME: move VME drivers out of
staging") stating:

    The VME device drivers have not moved out yet due to some API
    questions they are still working through, that should happen soon,
    hopefully.

However, this never happened: maintenance of drivers/vme effectively
stopped in 2017, with all subsequent changes being treewide cleanups.
No hardware driver remains in staging, only the limited user-level
access, and I just removed one of the two bridge drivers and the only
remaining board.

drivers/staging/vme/devices/ was recently moved to
drivers/staging/vme_user/, but as the vme_user driver is the only one
remaining for this subsystem, it is easier to just move the remaining
three source files into this directory rather than keeping the original
hierarchy.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20220606084109.4108188-3-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>