arm_gic: Rename GIC_X_TRIGGER to GIC_X_EDGE_TRIGGER

arm_gic: Rename GIC_X_TRIGGER to GIC_X_EDGE_TRIGGER

TRIGGER can really mean mean anything (e.g. was it triggered, is it
level-triggered, is it edge-triggered, etc.).  Rename to EDGE_TRIGGER to
make the code comprehensible without looking up the data structure.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Message-id: 1387606179-22709-2-git-send-email-christoffer.dall@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>