Input: delete MPU3050 driver

The MPU3050 driver in the input subsystem has been superseded by a proper
IIO driver found in drivers/iio/gyro/mpu3050*.

Patches have been submitted to remove all defconfig and related references
to the old driver and replace this input driver with the IIO driver.

So delete the input driver. Input was never a good fit for sensors anyway.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>