etherh and a handful of other odd drivers use different macros when building
8390.c.  Since we generate a single 8390.o and then link with it, in any
config with both oddball and normal 8390-based driver we will end up with
breakage in at least one of them.  Solution: take most of 8390.c into
lib8390.c and have 8390.c, etherh.c and the rest of oddballs #include it.
Helper macros are taken from 8390.h to whoever includes lib8390.c.  That
way odd drivers get separate instances of compiled 8390 stuff and stop
stepping on each other's toes.  8390.h gets cleaned up - we don't have
the cascade of ifdefs in there and are left with the stuff that can be
used by any 8390-based driver.  Current problems are exactly because of
that cascade - we attempt to choose the set of helpers by looking at config
and that, of course, doesn't work well when we have several sets needed
by various drivers in our config.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJeff Garzik <jeff@garzik.org>