pci_ids: Add AMD KERNCZ device ID support

The KERNCZ is new AMD SB/FCH generation name, like HUDSON2.
0x790b is the device ID for this generation.

Signed-off-by: Wan ZongShun <Vincent.Wan@amd.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>