clk: samsung: exynos5433: Fix error paths

Add checking the value returned by samsung_clk_alloc_reg_dump() and
devm_kcalloc(). While fixing this, also release all gathered clocks.

Fixes: 523d3de4

 ("clk: samsung: exynos5433: Add support for runtime PM")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
[s.nawrocki: squashed patch from K. Kozlowski adding missing slab.h header]
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>