Command usage cleanup

Remove command name from all command "usage" fields and update
common/command.c to display "name - usage" instead of
just "usage". Also remove newlines from command usage fields.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>

common/cmd_itest.c

@@ -190,6 +190,6 @@ int do_itest ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[] )
 
 U_BOOT_CMD(
 	itest, 4, 0, do_itest,
-	"itest\t- return true/false on integer compare\n",
+	"return true/false on integer compare",
 	"[.b, .w, .l, .s] [*]value1 <op> [*]value2\n"
 );