media: ipu-bridge: add mod_devicetable.h header inclusion

ACPI_ID_LEN is defined in mod_devicetable.h, so the header should
be guaranteed to included in ipu-bridge.h instead of the source
files which include ipu-bridge.h.

Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>