clk: bcm/kona: Do not use sizeof on pointer type

When sizeof is applied to a pointer typed expression, it gives
the size of the pointer. So, here do not use sizeof on pointer
type. Also, silent checkpatch.pl by using kmalloc_array over
kmalloc.

Note that this has no effect on runtime because 'parent_names'
is a pointer to a pointer.

Problem found using Coccinelle.

Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>