ALSA: usb: Constify snd_pcm_hardware definitions

Most of snd_pcm_hardware definitions are just copied to another object
as-is, hence we can define them as const for further optimization.

There should be no functional changes by this patch.

Link: https://lore.kernel.org/r/20200103081714.9560-3-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/caiaq/audio.c

@@ -30,7 +30,7 @@
 #define MAKE_CHECKBYTE(cdev,stream,i) \
 	(stream << 1) | (~(i / (cdev->n_streams * BYTES_PER_SAMPLE_USB)) & 1)
 
-static struct snd_pcm_hardware snd_usb_caiaq_pcm_hardware = {
+static const struct snd_pcm_hardware snd_usb_caiaq_pcm_hardware = {
 	.info 		= (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
 			   SNDRV_PCM_INFO_BLOCK_TRANSFER),
 	.formats 	= SNDRV_PCM_FMTBIT_S24_3BE,

sound/usb/usx2y/usbusx2yaudio.c

@@ -838,7 +838,7 @@ static int snd_usX2Y_pcm_prepare(struct snd_pcm_substream *substream)
 	return err;
 }
 
-static struct snd_pcm_hardware snd_usX2Y_2c =
+static const struct snd_pcm_hardware snd_usX2Y_2c =
 {
 	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
 				 SNDRV_PCM_INFO_BLOCK_TRANSFER |

sound/usb/usx2y/usx2yhwdeppcm.c

@@ -528,7 +528,7 @@ static int snd_usX2Y_usbpcm_prepare(struct snd_pcm_substream *substream)
 	return err;
 }
 
-static struct snd_pcm_hardware snd_usX2Y_4c =
+static const struct snd_pcm_hardware snd_usX2Y_4c =
 {
 	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
 				 SNDRV_PCM_INFO_BLOCK_TRANSFER |