spi: dt-bindings: amlogic, meson-gx-spicc: Add pinctrl names for SPI signal states

spi: dt-bindings: amlogic, meson-gx-spicc: Add pinctrl names for SPI signal states

SPI pins of the SPICC Controller in Meson-GX needs to be controlled by
pin biais when idle. Therefore define three pinctrl names:
- default: SPI pins are controlled by spi function.
- idle-high: SCLK pin is pulled-up, but MOSI/MISO are still controlled
by spi function.
- idle-low: SCLK pin is pulled-down, but MOSI/MISO are still controlled
by spi function.

Reported-by: Da Xue <da@libre.computer>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Amjad Ouled-Ameur <aouledameur@baylibre.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221004-up-aml-fix-spi-v4-1-0342d8e10c49@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>