phy: cadence: Sierra: Add support for PHY multilink configurations

Add support for multilink configuration of Sierra PHY. Currently,
maximum two links are supported.

Signed-off-by: Swapnil Jakhade <sjakhade@cadence.com>
Reviewed-by: Aswath Govindraju <a-govindraju@ti.com>
Link: https://lore.kernel.org/r/20211223060137.9252-13-sjakhade@cadence.com


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