egl/drm: Format code in platform_drm.c according to style guide.

This is a tiny housekeeping patch which does the following:
  * Limit lines to 78 or fewer characters.
According to the mesa coding style guidelines.

Signed-off-by: Mun Gwan-gyeong <elongbug@gmail.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

src/egl/drivers/dri2/platform_drm.c

@@ -230,7 +230,8 @@ get_back_bo(struct dri2_egl_surface *dri2_surf)
    if (dri2_surf->back->bo == NULL) {
       if (surf->base.modifiers)
          dri2_surf->back->bo = gbm_bo_create_with_modifiers(&dri2_dpy->gbm_dri->base,
-                                                            surf->base.width, surf->base.height,
+                                                            surf->base.width,
+                                                            surf->base.height,
                                                             surf->base.format,
                                                             surf->base.modifiers,
                                                             surf->base.count);