drm/modes: parse_cmdline: Add freestanding argument to drm_mode_parse_cmdline_options()

Add a freestanding function argument to drm_mode_parse_cmdline_options()
similar to how drm_mode_parse_cmdline_extra() already has this.

This is a preparation patch for allowing parsing of stand-alone options
without a mode before them, e.g.: video=HDMI-1:margin_right=14,...

Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191118155134.30468-6-hdegoede@redhat.com

drivers/gpu/drm/drm_modes.c

@@ -1592,6 +1592,7 @@ static int drm_mode_parse_cmdline_int(const char *delim, unsigned int *int_ret)
 }
 
 static int drm_mode_parse_cmdline_options(const char *str,
+					  bool freestanding,
 					  const struct drm_connector *connector,
 					  struct drm_cmdline_mode *mode)
 {
@@ -1663,6 +1664,9 @@ static int drm_mode_parse_cmdline_options(const char *str,
 		option = sep + 1;
 	} while (sep);
 
+	if (rotation && freestanding)
+		return -EINVAL;
+
 	mode->rotation_reflection = rotation;
 
 	return 0;
@@ -1855,6 +1859,7 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
 
 	if (options_ptr) {
 		ret = drm_mode_parse_cmdline_options(options_ptr + 1,
+						     false,
 						     connector, mode);
 		if (ret)
 			return false;