ARM: dts: nomadik: Fix polarity of SPI CS

The SPI DT bindings are for historical reasons a pitfall,
the ability to flag a GPIO line as active high/low with
the second cell flags was introduced later so the SPI
subsystem will only accept the bool flag spi-cs-high
to indicate that the line is active high.

It worked by mistake, but the mistake was corrected
in another commit.

The comment in the DTS file was also misleading: this
CS is indeed active high.

Fixes: cffbb02d ("ARM: dts: nomadik: Augment NHK15 panel setting")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/boot/dts/ste-nomadik-nhk15.dts

@@ -213,12 +213,13 @@ spi {
 		gpio-sck = <&gpio0 5 GPIO_ACTIVE_HIGH>;
 		gpio-mosi = <&gpio0 4 GPIO_ACTIVE_HIGH>;
 		/*
-		 * It's not actually active high, but the frameworks assume
-		 * the polarity of the passed-in GPIO is "normal" (active
-		 * high) then actively drives the line low to select the
-		 * chip.
+		 * This chipselect is active high. Just setting the flags
+		 * to GPIO_ACTIVE_HIGH is not enough for the SPI DT bindings,
+		 * it will be ignored, only the special "spi-cs-high" flag
+		 * really counts.
 		 */
 		cs-gpios = <&gpio0 6 GPIO_ACTIVE_HIGH>;
+		spi-cs-high;
 		num-chipselects = <1>;
 
 		/*