ASoC: rockchip: Fix an uninitialized variable compile warning

Paper over a trivial case leading to an uninitialized variable compile
warning:
  sound/soc/rockchip/rockchip_pdm.c:179:3: warning: ‘clk_out’ may be used uninitialized in this function [-Wmaybe-uninitialized]

Fixes: 624e8e00ac ("ASoC: rockchip: pdm: fixup pdm fractional div")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/rockchip/rockchip_pdm.c

@@ -158,7 +158,7 @@ static int rockchip_pdm_hw_params(struct snd_pcm_substream *substream,
 	struct rk_pdm_dev *pdm = to_info(dai);
 	unsigned int val = 0;
 	unsigned int clk_rate, clk_div, samplerate;
-	unsigned int clk_src, clk_out;
+	unsigned int clk_src, clk_out = 0;
 	unsigned long m, n;
 	bool change;
 	int ret;