ARM: dts: imx53-ppd: Use IRQ_TYPE_* constants

Replace magic numbers with IRQ_TYPE_* constants to improve
DT readability.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Reviewed-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>