staging: lustre: move files out of lustre/lnet/libcfs/linux/

There is no longer any value in having this separate
subdirectory, so promote the files in it.
Also tidy the Makefile a little to use the common "*-obj-y"
macro name.  This will allow individual files to be conditionally
compiled.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>