commit 07c52d6a upstream.

Add a spinlock to ensure that irq0_stat is not unintentionally altered
as the result of preemption.  Also removed unserviced irq0 interrupts
and removed irq1_stat since there is no bottom half service for those
interrupts.

Fixes: 1c1008c7 ("net: bcmgenet: add main driver file")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.16:
 - bcmgenet_irq_task() only handles UMAC_IRQ_LINK_UP and UMAC_IRQ_LINK_DOWN
   status flags
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>