ASoC: wm8978: clarify expression

cppcheck warning:

sound/soc/codecs/wm8978.c:727:57: style: Clarify calculation
precedence for '&' and '?'. [clarifyCalculation]
 enum wm8978_sysclk_src current_clk_id = clking & 0x100 ?
                                                        ^
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20210311004332.120901-7-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wm8978.c

@@ -724,7 +724,7 @@ static int wm8978_hw_params(struct snd_pcm_substream *substream,
 	/* Sampling rate mask = 0xe (for filters) */
 	u16 add_ctl = snd_soc_component_read(component, WM8978_ADDITIONAL_CONTROL) & ~0xe;
 	u16 clking = snd_soc_component_read(component, WM8978_CLOCKING);
-	enum wm8978_sysclk_src current_clk_id = clking & 0x100 ?
+	enum wm8978_sysclk_src current_clk_id = (clking & 0x100) ?
 		WM8978_PLL : WM8978_MCLK;
 	unsigned int f_sel, diff, diff_best = INT_MAX;
 	int i, best = 0;