For level sensitive interrupts, ISR bits are cleared when the input pin
is lowered. This is incorrect. Only software can clear ISR bits (via
IAR or direct write to ISR with !MER(2)).
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>