i2c: piix4: Fix request_region size

i2c: piix4: Fix request_region size

[ Upstream commit f43128c75202f29ee71aa83e6c320a911137c189 ]

Since '701dc207bf55 ("i2c: piix4: Avoid race conditions with IMC")' we
are using the SMBSLVCNT register at offset 0x8. We need to request it.

Fixes: 701dc207bf55 ("i2c: piix4: Avoid race conditions with IMC")
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>