thermal: imx_thermal: add module device table

Add the module device table declaration so the module can be loaded
automatically at boot time.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Eduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>