drm/sysfb: Split source file

Split drm_sysfb_helper.c into two source files. There's now one
source file for the mode-setting pipeline and one source file for
module meta data. Prepares for adding additional source code to
sysfb helpers.

v2:
- fix typo in commit message (Javier)

Signed-off-by: Thomas Zimmermann <[e-mail]>
Reviewed-by: Javier Martinez Canillas <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/gpu/drm/sysfb/Makefile

···
 # SPDX-License-Identifier: GPL-2.0-only
 
+drm_sysfb_helper-y := \
+	drm_sysfb.o \
+	drm_sysfb_modeset.o
 obj-$(CONFIG_DRM_SYSFB_HELPER)	+= drm_sysfb_helper.o
 
 obj-$(CONFIG_DRM_EFIDRM)	+= efidrm.o

drivers/gpu/drm/sysfb/drm_sysfb.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/module.h>
+
+#include "drm_sysfb_helper.h"
+
+MODULE_DESCRIPTION("Helpers for DRM sysfb drivers");
+MODULE_LICENSE("GPL");

drivers/gpu/drm/sysfb/drm_sysfb_helper.c drivers/gpu/drm/sysfb/drm_sysfb_modeset.c

···
 
 #include <linux/export.h>
 #include <linux/slab.h>
-#include <linux/module.h>
 
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
···
 #include <drm/drm_probe_helper.h>
 
 #include "drm_sysfb_helper.h"
-
-MODULE_DESCRIPTION("Helpers for DRM sysfb drivers");
-MODULE_LICENSE("GPL");
 
 struct drm_display_mode drm_sysfb_mode(unsigned int width,
 				       unsigned int height,

drivers/gpu/drm/sysfb/drm_sysfb_helper.h

···
 #include <drm/drm_modes.h>
 
 struct drm_format_info;
+struct drm_scanout_buffer;
+
+/*
+ * Display modes
+ */
 
 struct drm_display_mode drm_sysfb_mode(unsigned int width,
 				       unsigned int height,