gemini: splash banner on framebuffer console

The D-Link DIR-685 has a small screen with a framebuffer
console, so if we have this, when we start, display the
banner on this framebuffer console so the user know they
are running OpenWRT as root filesystem.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

target/linux/gemini/base-files/etc/board.d/03_splash

@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# OpenWRT splash screen if using framebuffer console
+
+if [ ! -d /sys/class/graphics/fbcon ] ; then
+	exit 0
+fi
+
+echo 0 > /sys/class/graphics/fbcon/cursor_blink
+cat /etc/banner > /dev/tty0