media: atomisp: Use kcalloc instead of kzalloc with multiply in sh_css.c

Use kcalloc instead of kzalloc with multiplication.

Link: https://lore.kernel.org/linux-media/20210508235622.300394-4-vrzh@vrzh.net


Signed-off-by: Martiros Shakhzadyan <vrzh@vrzh.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>