If an interrupt handler disables interrupts, the EOI function will
just reenable them.  This will put us in an endless loop when the
upcoming Ethernet driver patches are applied.

Only reenable the interrupt on EOI if it is not IRQ_DISABLED.  This
requires that the EOI function be separate from the ENABLE function.
We also rename the ACK functions to correspond with their function.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
To: gregkh@suse.de
Patchwork: http://patchwork.linux-mips.org/patch/840/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>