iio: light: isl76682: remove unreachable code

The function isl76682_read_raw cannot execute return -EINVAL up to 145
lines, delete the invalid code.

drivers/iio/light/isl76682.c:145 isl76682_read_raw() warn: ignoring unreachable code.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7698


Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Link: https://lore.kernel.org/r/20231208021715.32450-1-jiapeng.chong@linux.alibaba.com


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