Substantially raise the maximum avalon frequency for water-cooled, over-volted designs.

driver-avalon.h

@@ -41,7 +41,7 @@
 
 #define AVALON_DEFAULT_TIMEOUT 0x2D
 #define AVALON_MIN_FREQUENCY 256
-#define AVALON_MAX_FREQUENCY 450
+#define AVALON_MAX_FREQUENCY 1024
 #define AVALON_TIMEOUT_FACTOR 12690
 #define AVALON_DEFAULT_FREQUENCY 282
 #define AVALON_DEFAULT_MINER_NUM 0x20