iio:adc:at91: Relase mutex on error path in at91_adc_read_raw

This issue was reported by the mini_lock.cocci coccinelle semantic patch.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed