e100: fix irq leak on suspend/resume

From: Frederik Deweerdt <frederik.deweerdt@gmail.com>

The e100_resume() function should be calling netif_device_detach and
free_irq. This fixes multiple irq's being allocated after resume.
Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>