media: atomisp: use list_splice_init in atomisp_compat_css20.c

Using list_splice_init() instead of entire while-loops
in atomisp_compat_css20.c.

Link: https://lore.kernel.org/linux-media/20210617140926.887680-1-libaokun1@huawei.com


Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>