qeth: properly delete empty files.

Commit 64ef8957 ("qeth: remove EDDP")
removed the qeth_core_offl.[hc] files, but ended up doing so by just
patching them to zero size, rather than removing them properly.

Actually remove the files.
Reported-by: Andrew Price <andy@andrewprice.me.uk>
Cc: Frank Blaschka <frank.blaschka@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>