drm/i915: convert to new logging macros in i915/intel_memory_region.c

Replace the use of printk based logging macros with the new struct
drm_device based logging macro in i915/intel_memory_region.c.

Signed-off-by: Wambui Karuga <wambui.karugax@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1bf4d362e72c619843d44aac96c3561f54e4b23a.1578560355.git.wambui.karugax@gmail.com