msm: clock-8974: Correct pcm clock lookup name

Sound cards are not getting detected due to wrong
name of the clock used for msm-dai-q6.4106 device.
Correct the name to pcm_clk.

Change-Id: Ib54946b7d891fe1e6ce85e55e0a6d944cbd436ba
Signed-off-by: Phani Kumar Uppalapati <phanik@codeaurora.org>