ALSA: usb-audio: Increase max buffer size

The current limit of max buffer size 1MB seems too small for modern
devices with lots of channels and high sample rates.
Let's make bigger, 4MB.
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20220407212740.17920-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/pcm.c

@@ -659,7 +659,7 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
 #define hwc_debug(fmt, args...) do { } while(0)
 #endif
 
-#define MAX_BUFFER_BYTES	(1024 * 1024)
+#define MAX_BUFFER_BYTES	(4 * 1024 * 1024)
 #define MAX_PERIOD_BYTES	(512 * 1024)
 
 static const struct snd_pcm_hardware snd_usb_hardware =