clk: s5pv210: add missing call to samsung_clk_of_add_provider()

Commit d5e136a2

 ("clk: samsung: Register
clk provider only after registering its all clocks", merged to v3.17-rc1)
modified a way that driver registers registers to core framework. This
change has not been applied to s5pv210 clocks driver, which has been
merged in parallel to that commit. This patch adds a missing call to
samsung_clk_of_add_provider(), so the driver is operational again.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
CC: stable@vger.kernel.org  # v3.17+
Acked-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>