iio: buffer: remove attrcount_orig var from sysfs creation

The variable no longer does anything.
It should have been removed with commit 2e036804 ("iio: buffer: remove
'scan_el_attrs' attribute group from buffer struct").
That was about the last time this was needed.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>