mips: dts: ingenic: Switch to simple-audio-card,hp-det-gpios

Replace the deprecated "simple-audio-card,hp-det-gpio" property by
"simple-audio-card,hp-det-gpios" in Simple Audio Card device nodes.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>