iio: accel: sca3300: Extend the trigger buffer from 16 to 32 bytes

After added inclination angle channels, the trigger buffer size is
insufficient. Extend the buffer size from 16 to 32 bytes, and change
the trigger buffer from the struct to a u8 array to adapt the sensor
with/without inclination angles output.
New trigger buffer data:
  - SCA3300: 3 accel channels, temp, and timestamp.
  - SCL3300: 3 accel channels, temp, 3 incli channels, and timestamp.
Readjustment the scan index to make it consistent with the buffer data.

Signed-off-by: LI Qingwu <Qing-wu.Li@leica-geosystems.com.cn>
Link: https://lore.kernel.org/r/20220701023030.2527019-2-Qing-wu.Li@leica-geosystems.com.cn
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>