ASoC: sirf: provide pm-runtime functions when needed

ASoC: sirf: provide pm-runtime functions when needed

The newly introduced sirf-usp driver defines sirf_usp_pcm_{suspend,resume}
functions only when PM_RUNTIME is enabled, but also uses them when that
is disabled and only PM_SLEEP is turned on, resulting in this error:

../sound/soc/sirf/sirf-usp.c: In function 'sirf_usp_pcm_suspend':
../sound/soc/sirf/sirf-usp.c:308:3: error: implicit declaration of function 'sirf_usp_pcm_runtime_suspend' [-Werror=implicit-function-declaration]
   sirf_usp_pcm_runtime_suspend(dev);
   ^
../sound/soc/sirf/sirf-usp.c: In function 'sirf_usp_pcm_resume':
../sound/soc/sirf/sirf-usp.c:319:3: error: implicit declaration of function 'sirf_usp_pcm_runtime_resume' [-Werror=implicit-function-declaration]
   ret = sirf_usp_pcm_runtime_resume(dev);
   ^
cc1: some warnings being treated as errors

To fix that, this patch changes the #ifdef to CONFIG_PM, which
is enabled when at least one of PM_SLEEP or PM_RUNTIME are enabled.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@linaro.org>