iio: srf08: Remove redundant if statement

(!val) has been checked outside the loop, remove redundant (val &&)
from loop.

Signed-off-by: Li Zhengyu <lizhengyu3@huawei.com>
Acked-by: Andreas Klinger <ak@it-klinger.de>
Link: https://lore.kernel.org/r/20220523122755.90638-1-lizhengyu3@huawei.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>