arm: omap1: devices: need to return with a value

Get rid of the following warning:

arch/arm/mach-omap1/devices.c: In function 'omap_init_wdt':
arch/arm/mach-omap1/devices.c:298: warning: 'return' with
no value, in function returning non-void

while at that, also change:

platform_device_register();
return 0;

into:

return platform_device_register();

Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>