ARM: 5878/1: ep93xx: register the pwm devices on the edb93xx dev boards

Add the platform init code to register the pwm devices that exist
on the various edb93xx development boards.

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>