arm: exynos: Use proper ADC device name

arm: exynos: Use proper ADC device name

Since commit 4213609cc7 ("drivers: core: use strcmp when find device by
name") one has to provide full name to get requested object. Fix the code
used to detect Odroid board revision to use proper ADC device name then.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
[backport of mainline commit fa06669d0181b2c92ba86fb6c40a4cb0c196b13c]

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Change-Id: I2f7bda9d69826b38fd6d3a193876b3fe502d8859