phy: qcom-ufs: remove failure when rx/tx_iface_clk are absent

Since in future UFS Phy's the tx_iface_clk and rx_iface_clk
are no longer exist, we should not fail when their initialization
fail, but rather just report with debug message.

Change-Id: I87e4deca632d4d4ee9e35a03f2fc9c22987255b3
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>
[cang@codeaurora.org: resolved trivial merge conflicts]
Signed-off-by: Can Guo <cang@codeaurora.org>