drm/i915/pxp: remove useless includes

Not needed.
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/01c4ea0cea17eead027c83dc9eaca3c181ce3a24.1639142167.git.jani.nikula@intel.com

drivers/gpu/drm/i915/pxp/intel_pxp_types.h

@@ -7,9 +7,7 @@
 #define __INTEL_PXP_TYPES_H__
 
 #include <linux/completion.h>
-#include <linux/list.h>
 #include <linux/mutex.h>
-#include <linux/spinlock.h>
 #include <linux/types.h>
 #include <linux/workqueue.h>