drm/atomic-helper: Remove _HELPER_ infix from DRM_PLANE_HELPER_NO_SCALING

Rename DRM_PLANE_HELPER_NO_SCALING to DRM_PLANE_NO_SCALING. The constant
is not really a helper, but rather a characteristic of the plane itself.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220720083058.15371-4-tzimmermann@suse.de