e100: free IRQ to remove warningwhenrebooting

Adapted from Ian Wienand <ianw@gelato.unsw.edu.au>

Explicitly free the IRQ before removing the device to remove a
warning "Destroying IRQ without calling free_irq"

Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Cc: Ian Wienand <ianw@gelato.unsw.edu.au>
Signed-off-by: Jeff Garzik <jeff@garzik.org>