i2c: i801: Centralize configuring non-block commands in i801_simple_transaction

Currently configuring command register settings is distributed over multiple
functions. At first centralize this for non-block commands in
i801_simple_transaction().

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>