phy: uniphier-pcie: Add compatible string and SoC-dependent data for NX1 SoC

Add basic support for UniPhier NX1 SoC. This includes a compatible string,
SoC-dependent data, and a function that set to 2-lane mode.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Link: https://lore.kernel.org/r/1635503947-18250-5-git-send-email-hayashi.kunihiko@socionext.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>