dmaengine: at_hdmac: Extend the Flow Controller bitfield to three bits

dmaengine: at_hdmac: Extend the Flow Controller bitfield to three bits

Some chips have two bits (e.g SAMA5D3), and some have three (e.g.
SAM9G45). A field width of three is compatible as long as valid
values are used for the different chips.

There is no current use of any value needing three bits, so the
fixed bug is relatively benign.

Fixes: d8840a7edcf0 ("dmaengine: at_hdmac: Use bitfield access macros")
Cc: stable@vger.kernel.org
Reviewed-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Signed-off-by: Peter Rosin <peda@axentia.se>
Link: https://lore.kernel.org/r/e2c898ba-c3a3-5dd3-384b-0585661c79f2@axentia.se
Signed-off-by: Vinod Koul <vkoul@kernel.org>