smpl_buf: Remove unused clk_rt variable

During 87b7d098e517470fec53ac13a28d1d0fa7b16bb4 we dropped support for
UHD specific functionalitites, and so clk_rt is not needed anymore.

Change-Id: I37403e085ed6a541bbdecf64f1f9a821ff2753a4
3 files changed