phy: qcom-ufs: add support for 20nm phy

This change adds a support for a 20nm qcom-ufs phy that is required in
platforms that use ufs-qcom controller.

Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>
Reviewed-by: Dov Levenglick <dovl@codeaurora.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>