drm/i915: Make i2c lock ops static

drm/i915: Make i2c lock ops static

Make gmbus_lock_ops and proxy_lock_ops static to appease sparse
intel_i2c.c:652:34: warning: symbol 'gmbus_lock_ops' was not declared. Should it be static?
intel_sdvo.c:2981:34: warning: symbol 'proxy_lock_ops' was not declared. Should it be static?

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Fixes: a85066840d29 ("drm/i915: Rework sdvo proxy i2c locking")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170901143123.7590-2-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>