iio: buffer: Remove redundant assignment to in_loc

iio: buffer: Remove redundant assignment to in_loc

Variable in_loc is being assigned a value from a calculation
however the assignment is never read, so this redundant assignment
can be removed.

Clean up the following clang-analyzer warning:

drivers/iio/industrialio-buffer.c:929:3: warning: Value stored to
'in_loc' is never read [clang-analyzer-deadcode.DeadStores].

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Link: https://lore.kernel.org/r/1621246317-62725-1-git-send-email-jiapeng.chong@linux.alibaba.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>