ARM: dts: exynos: Fix pinctrl definition for eMMC RTSN line on Odroid X2/U3

Commit 225da7e6 ("ARM: dts: add eMMC reset line for
exynos4412-odroid-common") added MMC power sequence for eMMC card of
Odroid X2/U3. It reused generic sd1_cd pin control configuration node
and only disabled pull-up. However that time the pinctrl configuration
was not applied during MMC power sequence driver initialization. This
has been changed later by commit d97a1e5d

 ("mmc: pwrseq: convert to
proper platform device").

It turned out then, that the provided pinctrl configuration is not
correct, because the eMMC_RTSN line is being re-configured as 'special
function/card detect function for mmc1 controller' not the simple
'output', thus the power sequence driver doesn't really set the pin
value. This in effect broke the reboot of Odroid X2/U3 boards. Fix this
by providing separate node with eMMC_RTSN pin configuration.

Cc: <stable@vger.kernel.org>
Reported-by: Markus Reichl <m.reichl@fivetechno.de>
Suggested-by: Ulf Hansson <ulf.hansson@linaro.org>
Fixes: 225da7e6

 ("ARM: dts: add eMMC reset line for exynos4412-odroid-common")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>