drm/i915/gem: use spinlock_t instead of struct spinlock

spinlock_t is one case where the typedef is to be preferred over struct
spinlock.

Fixes: 42fb60d ("drm/i915/gem: Don't leak non-persistent requests on changing engines")
Cc: Chris Wilson <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Reviewed-by: Chris Wilson <[email protected]>
Signed-off-by: Jani Nikula <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

drivers/gpu/drm/i915/gem/i915_gem_context_types.h

@@ -181,7 +181,7 @@ struct i915_gem_context {
 	char name[TASK_COMM_LEN + 8];
 
 	struct {
-		struct spinlock lock;
+		spinlock_t lock;
 		struct list_head engines;
 	} stale;
 };