fix cppcheck warning:

sound/core/timer.c:1286:9: style: Clarify calculation precedence for
'&' and '?'. [clarifyCalculation]
        ? "running" : "stopped");
        ^
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200902212133.30964-6-pierre-louis.bossart@linux.intel.comSigned-off-by: Takashi Iwai <tiwai@suse.de>