ep93xx: Show gpio interrupt type in debugfs output.

EP93xx uses a private implementation for the debugfs output.
Modify this output so it includes the interrupt type when the
gpio is configured as an interrupt
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>