iio:accel:mma8452: fix _get_hp_filter_index

To iterate through the available frequencies of mma8452_hp_filter_cutoff[],
the array size of a row of that table needs to be provided to
_get_int_plus_micros_index().

Fixes: 	1e79841a ("iio: mma8452: Add highpass filter configuration.")
Signed-off-by: NHartmut Knaack <knaack.h@gmx.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

drivers/iio/accel/mma8452.c

@@ -229,7 +229,7 @@ static int mma8452_get_hp_filter_index(struct mma8452_data *data,
 	int i = mma8452_get_odr_index(data);
 
 	return mma8452_get_int_plus_micros_index(mma8452_hp_filter_cutoff[i],
-		ARRAY_SIZE(mma8452_scales[0]), val, val2);
+		ARRAY_SIZE(mma8452_hp_filter_cutoff[0]), val, val2);
 }
 
 static int mma8452_read_hp_filter(struct mma8452_data *data, int *hz, int *uHz)