ASoC: add static inline funcs to fix a compiling issue

When CONFIG_PM_SLEEP is not selected, calling funcs
snd_soc_suspend and _resume will generate a compiling
issue.

Here add static inline stub functions to fix it.

Signed-off-by: Jie Yang <yang.jie@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>