ASoC: audio-ext-clk: Replace clock dummy ops

Replace clock framework's clock dummy ops with audio external
clock ops to access correct structure that avoids out of bounds
memory access.

Change-Id: I51db63bba414cff0343cbf68e90b1e1bbf7929ac
Signed-off-by: Sudheer Papothi <spapothi@codeaurora.org>