clk: samsung: Remove useless check for return value of samsung_clk_init

The samsung_clk_init() cannot return NULL. Either it returns allocated
memory or it panics.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>