ARM: S5PV210: Remove support for board files

Since all in-tree boards have been moved to device tree, we can now drop
legacy code and make mach-s5pv210 DT-only. This patch does it.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>