ALSA: pci/rme9652/hdspm: remove always true condition

Fix W=1 warning:

sound/pci/rme9652/hdspm.c: In function ‘hdspm_autosync_ref’:
sound/pci/rme9652/hdspm.c:3030:16: warning: comparison of unsigned
expression >= 0 is always true [-Wtype-limits]
 3030 |   if ((syncref >= HDSPM_AES32_AUTOSYNC_FROM_WORD) &&
      |                ^~

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200702193604.169059-16-pierre-louis.bossart@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>