bus: imx-weim: use module_platform_driver()

Switch from module_platform_driver_probe() to module_platform_driver().
The former is not suitable for booting with device tree as the driver
will be registered before the device and thus won't be probed again
when the device is present.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>