drm/i915: move the DRIVER_* macros to i915_driver.[ch]

The macros are more at home in i915_driver.[ch].

v2: Rebase

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220209123121.3337496-1-jani.nikula@intel.com