PCI: j721e: Add PCIe 4x lane selection support

Add support for setting of two-bit field that allows selection of 4x lane
PCIe which was previously limited to only 2x lanes.

Link: https://lore.kernel.org/linux-pci/20231128054402.2155183-5-s-vadapalli@ti.com


Signed-off-by: Matt Ranostay <mranostay@ti.com>
Signed-off-by: Achal Verma <a-verma1@ti.com>
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Roger Quadros <rogerq@kernel.org>