colibri_imx7: use splashcreen value instead of legacy function

Set proper splashscreen env value instead of calling legacy function
to show embed boot logo.

Fixes: 195011b24d("colibri-imx7: fix splash logo drawing")
Signed-off-by: Igor Opaniuk <igor.opaniuk@toradex.com>

board/toradex/colibri_imx7/colibri_imx7.c

@@ -356,8 +356,6 @@ int board_late_init(void)
 {
 #if defined(CONFIG_DM_VIDEO)
 	setup_lcd();
-
-	show_boot_logo();
 #endif
 	return 0;
 }