atl1c: Fix work event interrupt/task races

atl1c: Fix work event interrupt/task races

commit cb771838715b1c470bc5735bdae709b33b18e0ad upstream.

The mechanism used to initiate work events from the interrupt
handler has a classic read/modify/write race between the interrupt
handler that sets the condition, and the worker task that reads and
clears the condition. Close these races by using atomic
bit fields.

Cc: Jie Yang <jie.yang@atheros.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>