Input: wacom - relax Bamboo stylus ID check

Bit 0x02 always means tip versus eraser. Bit 0x01 is something related
to version of stylus and different values are starting to be used.

Relaxing proximity check is required to be used with 3rd generation
Bamboo Pen and Touch tablets.

Signed-off-by: Chris Bagwell <chris@cnpbagwell.com>
Acked-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>