i2c: piix4: Enable EFCH MMIO for Family 17h+

Enable EFCH MMIO using check for SMBus PCI revision ID value 0x51 or
greater. This PCI revision ID check will enable family 17h and future
AMD processors with the same EFCH SMBus controller HW.

Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>