i2c-davinci: Move dev_dbg statement for more output

Previously the dev_dbg only printed if no error.
Printing also on an error is more useful

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>