ALSA: caiaq: More constifications

Apply const prefix to each possible place: the rate table, the
controller tables, and the key tables.

Just for minor optimization and no functional changes.

Link: https://lore.kernel.org/r/20200105144823.29547-13-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/caiaq/input.c b/sound/usb/caiaq/input.c
index 533eb69..1e2cf2f 100644
--- a/sound/usb/caiaq/input.c
+++ b/sound/usb/caiaq/input.c
@@ -14,13 +14,13 @@
 #include "device.h"
 #include "input.h"
 
-static unsigned short keycode_ak1[] =  { KEY_C, KEY_B, KEY_A };
-static unsigned short keycode_rk2[] =  { KEY_1, KEY_2, KEY_3, KEY_4,
+static const unsigned short keycode_ak1[] =  { KEY_C, KEY_B, KEY_A };
+static const unsigned short keycode_rk2[] =  { KEY_1, KEY_2, KEY_3, KEY_4,
 					 KEY_5, KEY_6, KEY_7 };
-static unsigned short keycode_rk3[] =  { KEY_1, KEY_2, KEY_3, KEY_4,
+static const unsigned short keycode_rk3[] =  { KEY_1, KEY_2, KEY_3, KEY_4,
 					 KEY_5, KEY_6, KEY_7, KEY_8, KEY_9 };
 
-static unsigned short keycode_kore[] = {
+static const unsigned short keycode_kore[] = {
 	KEY_FN_F1,      /* "menu"               */
 	KEY_FN_F7,      /* "lcd backlight       */
 	KEY_FN_F2,      /* "control"            */
@@ -60,7 +60,7 @@ static unsigned short keycode_kore[] = {
 #define MASCHINE_PADS      (16)
 #define MASCHINE_PAD(X)    ((X) + ABS_PRESSURE)
 
-static unsigned short keycode_maschine[] = {
+static const unsigned short keycode_maschine[] = {
 	MASCHINE_BUTTON(40), /* mute       */
 	MASCHINE_BUTTON(39), /* solo       */
 	MASCHINE_BUTTON(38), /* select     */