i2c: i801: use i2c_mark_adapter_suspended/resumed

When entering the suspend callback, at first we should ensure that
transfers are finished and I2C core can't start further transfers.
Use i2c_mark_adapter_suspended() for this purpose, and complement it
with a call to i2c_mark_adapter_resumed() in the resume path.

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