media: atomisp: remove duplicate include in sh_css

'ia_css_isys.h' included in 'sh_css.c' is duplicated.
It is also included in the 30th line.

Link: https://lore.kernel.org/linux-media/20210306121104.218696-1-zhang.yunkai@zte.com.cn


Signed-off-by: Zhang Yunkai <zhang.yunkai@zte.com.cn>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>