jme: fix irq storm after suspend/resume

If the device is down during suspend/resume, interrupts are enabled
without a registered interrupt handler, causing a storm of
unhandled interrupts until the IRQ is disabled because "nobody
cared".

Instead, check that the device is up before touching it in the
suspend/resume code.

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=39112



Helped-by: Adrian Chadd <adrian@freebsd.org>
Helped-by: Mohammed Shafi <shafi.wireless@gmail.com>
Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: David S. Miller <davem@davemloft.net>