i2c: i801: Don't read back cleared status in i801_check_pre()

I see no need to read back the registers to verify that the bits
have actually been cleared. I can't imagine any scenario where
the bits would remain set after a write to them.

Whilst at it, change involved syslog messages to use pci_dbg() et al.
to simplify them.

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