The uninitialized default of 0 for gpio_hp_det and gpio_mic_det doesn't
play well with asm-generic's gpio_is_valid():

	static inline bool gpio_is_valid(int number)
	{
		return number >= 0 && number < ARCH_NR_GPIOS;
	}

Hence on r8a7740/armadillo-legacy:

	sh-mobile-hdmi sh-mobile-hdmi: SH Mobile HDMI Audio Codec
	sh-mobile-hdmi sh-mobile-hdmi: ASoC: DAPM unknown pin Headphones
	sh-mobile-hdmi sh-mobile-hdmi: ASoC: DAPM unknown pin Mic Jack

After that the kernel log is spammed ca. 7 times per second with:

	sh-mobile-hdmi sh-mobile-hdmi: ASoC: DAPM unknown pin Headphones

Initialize the GPIO numbers with a negative number (-ENOENT) to fix this.

Fixes: 3fe24032 ("ASoC: simple-card: Add mic and hp detect gpios.")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>