Change #warning to FIXME for depca

This ancient ISA driver should probably be removed.
It is hard to get a card to test it with, and there
are comments to the effect that it cannot work with
relocation.  I would be quite interested to get a
bug report by someone who actually has this card.

src/drivers/net/depca.c

@@ -1,4 +1,4 @@
-#warning "depca.c: FIXME: fix relocation"
+/* #warning "depca.c: FIXME: fix relocation" */
 
 #if 0
 /* Not fixed for relocation yet. Probably won't work relocated above 16MB */