ALSA: usx2y: More constifications

Apply const prefix to each possible place: the string array and the
parameter tables and callers.

Just for minor optimization and no functional changes.

Link: https://lore.kernel.org/r/20200105144823.29547-23-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/usx2y/usX2Yhwdep.c

@@ -94,7 +94,7 @@ static __poll_t snd_us428ctls_poll(struct snd_hwdep *hw, struct file *file, poll
 static int snd_usX2Y_hwdep_dsp_status(struct snd_hwdep *hw,
 				      struct snd_hwdep_dsp_status *info)
 {
-	static char *type_ids[USX2Y_TYPE_NUMS] = {
+	static const char * const type_ids[USX2Y_TYPE_NUMS] = {
 		[USX2Y_TYPE_122] = "us122",
 		[USX2Y_TYPE_224] = "us224",
 		[USX2Y_TYPE_428] = "us428",

sound/usb/usx2y/usbusx2yaudio.c

@@ -549,7 +549,7 @@ static int snd_usX2Y_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
  * if sg buffer is supported on the later version of alsa, we'll follow
  * that.
  */
-static struct s_c2
+static const struct s_c2
 {
 	char c1, c2;
 }
@@ -589,7 +589,7 @@ static struct s_c2
 	{ 0x18, 0x7C},
 	{ 0x18, 0x7E}
 };
-static struct s_c2 SetRate48000[] =
+static const struct s_c2 SetRate48000[] =
 {
 	{ 0x14, 0x09},	// this line sets 48000, well actually a little less
 	{ 0x18, 0x40},	// only tascam / frontier design knows the further lines .......
@@ -642,7 +642,7 @@ static int usX2Y_rate_set(struct usX2Ydev *usX2Y, int rate)
 	int			err = 0, i;
 	struct snd_usX2Y_urbSeq	*us = NULL;
 	int			*usbdata = NULL;
-	struct s_c2		*ra = rate == 48000 ? SetRate48000 : SetRate44100;
+	const struct s_c2	*ra = rate == 48000 ? SetRate48000 : SetRate44100;
 
 	if (usX2Y->rate != rate) {
 		us = kzalloc(sizeof(*us) + sizeof(struct urb*) * NOOF_SETRATE_URBS, GFP_KERNEL);