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

Convert remaining instances of the printk based logging macros in
i915/gt/intel_gt to the struct drm_device based logging macros.

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/20200128071437.9284-7-wambui.karugax@gmail.com