msm: clock-8974: Correct lookup entries for HDMI Tx device

HDMI Tx device uses two iface clocks. mdss_ahb_clk is needed to
access registers for all mdss hw modules including HDMI Tx
controller and mdss_hdmi_ahb_clk is needed during HDCP
authentication. Name them iface_clk and alt_iface_clk respectively.

Change-Id: I891521e591fdbdb266aeab2279dac5288b5732ac
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>