ASoC: davinci-mcasp: Fix clang warning without CONFIG_PM

Building with clang shows a variable that is only used by the
suspend/resume functions but defined outside of their #ifdef block:

sound/soc/ti/davinci-mcasp.c:48:12: error: variable 'context_regs' is not needed and will not be emitted

We commonly fix these by marking the PM functions as __maybe_unused,
but here that would grow the davinci_mcasp structure, so instead
add another #ifdef here.

Fixes: 1cc0c054f3 ("ASoC: davinci-mcasp: Convert the context save/restore to use array")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/ti/davinci-mcasp.c

@@ -45,6 +45,7 @@
 
 #define MCASP_MAX_AFIFO_DEPTH	64
 
+#ifdef CONFIG_PM
 static u32 context_regs[] = {
 	DAVINCI_MCASP_TXFMCTL_REG,
 	DAVINCI_MCASP_RXFMCTL_REG,
@@ -68,6 +69,7 @@ struct davinci_mcasp_context {
 	u32	*xrsr_regs; /* for serializer configuration */
 	bool	pm_state;
 };
+#endif
 
 struct davinci_mcasp_ruledata {
 	struct davinci_mcasp *mcasp;