Input: elan_i2c - remove unneeded MODULE_VERSION() usage

MODULE_VERSION is useless for in-kernel drivers, so just remove all
usage of it in the elan_i2c mouse driver.  Now that this is gone, the
ELAN_DRIVER_VERSION define was also removed as it was pointless.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>