lavd/alsa: Double maximum alsa buffer size.

Fixes recording from ATI Wonder 600 USB adapter, regression since e35c674d.

Reported and analyzed by: Marco Paolieri, paolieri at gmail

libavdevice/alsa.h

@@ -43,7 +43,7 @@
 
 typedef void (*ff_reorder_func)(const void *, void *, int);
 
-#define ALSA_BUFFER_SIZE_MAX 65536
+#define ALSA_BUFFER_SIZE_MAX 131072
 
 typedef struct AlsaData {
     AVClass *class;