phy: qcom-ufs: Catch devm_phy_create failure in ufs_qcom_phy_generic_probe

Current code does NULL test against return value of ufs_qcom_phy_generic_probe.
However, in the case of devm_phy_create() failure, ufs_qcom_phy_generic_probe
does not return NULL. Fix it.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>