From: Marc Zyngier <mzyngier@freesurf.fr>, Christoph Hellwig

I'd like to kill willy's CONFIG_EISA_ALWAYS kludge.  So make EISA_bus a
variable always when CONFIG_EISA is set and initialize it to 1 for alpha.
We probably want to do that only if the system actually supports eisa, but
I keep the old behaviour for now.