ITE: drivers/i2c: Add command queue mode

Adding command queue mode can reduce the time between each byte to
improve the I2C bus clock stretching during I2C transaction.

I2C command queue mode of it8xxx2 can support I2C APIs including:
i2c_write(), i2c_read(), i2c_burst_read.

Test:
1. tests\drivers\i2c\i2c_api --> pass
2. Reading 16 bytes of data through i2c_burst_read() can reduce
   0.72ms(2.54ms->1.82ms) compared to the original pio mode when the
   frequency is 100KHz.
3. krabby platform can boot normally.

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