ARM: dts: Fix wrong compatible string for Exynos3250 ADC

This patchset fix wrong compatible string for Exynos3250 ADC. Exynos3250 SoC
need to control only special clock for ADC. Exynos SoC except for Exynos3250
has not included special clock for ADC. The exynos ADC driver can control
special clock if compatible string is 'exynos3250-adc-v2'.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>