drm: Rename plane atomic_check state names

Most drivers call the argument to the plane atomic_check hook simply
state, which is going to conflict with the global atomic state in a
later rework. Let's rename it to new_plane_state (or new_state depending
on the convention used in the driver).

This was done using the coccinelle script below, and built tested:

@ plane_atomic_func @
identifier helpers;
identifier func;
@@

 static const struct drm_plane_helper_funcs helpers = {
 	.atomic_check = func,
 };

@ has_old_state @
identifier plane_atomic_func.func;
identifier plane;
expression e;
symbol old_state;
symbol state;
@@

 func(struct drm_plane *plane, struct drm_plane_state *state)
 {
 	...
 	struct drm_plane_state *old_state = e;
 	...
 }

@ depends on has_old_state @
identifier plane_atomic_func.func;
identifier plane;
symbol old_state;
@@

 func(struct drm_plane *plane,
-	struct drm_plane_state *state
+	struct drm_plane_state *new_state
     )
 {
 	<+...
-	state
+	new_state
	...+>
 }

@ has_state @
identifier plane_atomic_func.func;
identifier plane;
symbol state;
@@

 func(struct drm_plane *plane, struct drm_plane_state *state)
 {
 	...
 }

@ depends on has_state @
identifier plane_atomic_func.func;
identifier plane;
symbol old_state;
@@

 func(struct drm_plane *plane,
-	struct drm_plane_state *state
+	struct drm_plane_state *new_plane_state
     )
 {
 	<+...
-	state
+	new_plane_state
	...+>
 }

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210219120032.260676-2-maxime@cerno.tech