ARM: dts: exynos: Fix max voltage for buck8 regulator on Odroid XU3/XU4

The maximum voltage value for buck8 regulator on Odroid XU3/XU4 boards is
set too low. Increase it to the 2000mV as specified on the board schematic.
So far the board worked fine, because of the bug in the PMIC driver, which
used incorrect step value for that regulator. It interpreted the voltage
value set by the bootloader as 1225mV and kept it unchanged. The regulator
driver has been however fixed recently in the commit 56b5d4ea


("regulator: s2mps11: Fix steps for buck7, buck8 and LDO35"), what results
in reading the proper buck8 value and forcing it to 1500mV on boot. This
is not enough for proper board operation and results in eMMC errors during
heavy IO traffic. Increasing maximum voltage value for buck8 restores
original driver behavior and fixes eMMC issues.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: 86a2d2ac ("ARM: dts: Add dts file for Odroid XU3 board")
Fixes: 56b5d4ea

 ("regulator: s2mps11: Fix steps for buck7, buck8 and LDO35")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>