pl330: Don't inhibit ES bits on INTEN

pl330: Don't inhibit ES bits on INTEN

This if-else logic inhibits setting of the event status (ES) bits
when interrupts are enabled. This is incorrect. ES should be set
regardless on INTEN state. INTEN only inhibits the signalling of
events to PL330 threads, not setting of the ES register.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>