Documentation: power: Use kcalloc() instead of kzalloc()

As noted in the "Deprecated Interfaces, Language Features, Attributes,
and Conventions" documentation [1], size calculations (especially
multiplication) should not be performed in memory allocator (or similar)
function arguments due to the risk of them overflowing. This could lead
to values wrapping around and a smaller allocation being made than the
caller was expecting. Using those allocations could lead to linear
overflows of heap memory and other misbehaviors.

So, in the example code use the purpose specific kcalloc() function
instead of the argument size * count in the kzalloc() function.

At the same time, modify the translations accordingly.

Signed-off-by: Erick Archer <erick.archer@gmx.com>
Reviewed-by: Hu Haowen <2023002089@link.tyut.edu.cn>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Hu Haowen <2023002089@link.tyut.edu.cn>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>