Add support for Gemini Lake LPSS UARTs.

With this patch:
% dmesg | grep -i uart
uart2: <Intel Gemini Lake SIO/LPSS UART 0> mem 0xa1426000-0xa1426fff,0xa1425000-0xa1425fff irq 4 at device 24.0 on pci0
uart3: <Intel Gemini Lake SIO/LPSS UART 1> mem 0xa1424000-0xa1424fff,0xa1423000-0xa1423fff irq 5 at device 24.1 on pci0
uart4: <Intel Gemini Lake SIO/LPSS UART 2> mem 0xfea10000-0xfea10fff irq 6 at device 24.2 on pci0
uart5: <Intel Gemini Lake SIO/LPSS UART 3> mem 0xa1422000-0xa1422fff,0xa1421000-0xa1421fff irq 7 at device 24.3 on pci0

PR: 256101
Submitted by: Daniel Ponte <amigan@gmail.com>
MFC after: 1 week