clk: samsung: Delete a memory allocation error message in clk-cpu.c

Omit an extra message for a memory allocation failure
in exynos_register_cpu_clock() function.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>