Input: usbtouchscreen - support DMC devices with empty EEPROM

A reply of 0x0600 means all OK, 0x1501 means OK, but EEPROM empty.
The behavior with an empty EEPROM is the same as without one at all
so do not fail loading the driver.

Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>