Input: cros_ec_keyb - drop unnecessary call to dev_set_drvdata and other changes

There is no call to platform_get_drvdata() or dev_get_drvdata().
Drop the unnecessary call to dev_set_drvdata().
Other relevant changes:
  Use existing variable 'dev' instead of dereferencing it several times

This conversion was done automatically with coccinelle using the
following semantic patches. The semantic patches and the scripts
used to generate this commit log are available at
https://github.com/groeck/coccinelle-patches



- Drop dev_set_drvdata()
- Use local variable 'struct device *dev' consistently

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>