cbfstool: move verbose to common.c

In order for multiple tools to use the common code found
in common.c place the verbose variable within common.c's
compilation unit.

Change-Id: I71660a5fd4d186ddee81b0da8b57ce2abddf178a
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/5364
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

util/cbfstool/cbfstool.c

@@ -37,7 +37,6 @@ struct command {
 	int (*function) (void);
 };
 
-int verbose = 0;
 static struct param {
 	char *cbfs_name;
 	char *name;

util/cbfstool/common.c

@@ -28,6 +28,7 @@
 #include "cbfs.h"
 
 /* Utilities */
+int verbose = 0;
 
 /* Small, OS/libc independent runtime check for endianess */
 int is_big_endian(void)