This patch prevents the module hdm_dim2 from breaking the build in case
HAS_IOMEM is not configured.

Reported-by: <fengguang.wu@intel.com>
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>