ite: drivers/i2c: it8xxx2: fix i2c_reset issue

After i2c_reset, there is still no external pull-up I2C bus,
and finishing off the rest of loop causes the code to hang
indefinitely.
This patch fixes that if I2C bus is not available(No external
pull-up), dropping the transaction.

Signed-off-by: Tim Lin <tim2.lin@ite.corp-partner.google.com>