spi: spi-s3c64xx: Report more information when errors occur

Report amount of pending data when a transfer stops due to errors.

Report if DMA was used to transfer data and print the status code.

Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
Link: https://lore.kernel.org/r/20201002122243.26849-5-l.stelmach@samsung.com


Signed-off-by: Mark Brown <broonie@kernel.org>