clk-kona-setup: Use kmalloc_array() in parent_process()

A multiplication for the size determination of a memory allocation
indicated that an array data structure should be processed.
Thus use the corresponding function "kmalloc_array".

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Alex Elder <elder@linaro.org>
[sboyd@codeaurora.org: Save a line]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>