Input: elants_i2c - get product id on recovery mode for FW update

We use hw version to construct name of file holding touchscreen firmware,
so let's try reading it even if touchscreen initialization fails (the
firmware supports reading product/hardware id even when device is in
recovery/boot mode).

Signed-off-by: Johnny Chuang <johnny.chuang@emc.com.tw>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>