Input: dm355evm_keys - drop unnecessary call to input_set_drvdata

Since there is no call to dev_get_drvdata() or input_get_drvdata(),
the call to input_set_drvdata() is unnecessary and can be dropped.

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