mach-orion5x/common.c: remove unnecessary (void *) casts

The (void *) cast is not needed when setting dev.platform_data to the
address of the data. Remove the casts.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>