i2c: designware_i2c: Support ACPI table generation

Update the PCI driver to generate ACPI information so that Linux has the
full information about each I2C bus.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
[bmeng: Correct one typo in dw_i2c_gen_speed_config() comments]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>