When transfer timeout, give -EAGAIN to the message's status, and it can
make the spi device driver choose repeated transimation or not. And if
transfer timeout, output some useful information for tracing the issue.
Signed-off-by: Jiwei Sun <jiwei.sun@windriver.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>