drm/i915/gt: remove a static inline that requires including i915_drv.h

It's actively harmful to add static inlines in headers that require you
to pull in more headers. Remove the include added in commit f1530f91
("drm/i915/gt: Apply workaround 22016122933 correctly"). We see that
there's already an implicit dependency on the i915_drv.h that we need to
address too.

Cc: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Fei Yang <fei.yang@intel.com>
Cc: Jonathan Cavitt <jonathan.cavitt@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230921162456.3889375-1-jani.nikula@intel.com