i2c: davinci: Use struct name not type with devm_kzalloc()

This reduces chance of error if the type of "dev" changes. While here
remove extra error print out, this is not usually done for memory
allocation failures.

Signed-off-by: Andrew Davis <afd@ti.com>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>