ARM: dts: s3c2416: Add labels to S3C2416 nodes

Add new labels to certain nodes on S3C2416 so they could be easily
referenced by board DTS files.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>