orion.h: Quell compiler warning on MinGW

Quell the following error on MinGW:

  CC       orion.lo
In file included from ../../hamlib-3.0~git/tentec/orion.c:86:0:
../../hamlib-3.0~git/tentec/orion.h:34:0: warning: "TRUE" redefined [enabled by default]
c:\mingw\bin\../lib/gcc/mingw32/4.6.2/../../../../include/windef.h:55:0: note: this is the location of the previous definition
../../hamlib-3.0~git/tentec/orion.h:35:0: warning: "FALSE" redefined [enabled by default]
c:\mingw\bin\../lib/gcc/mingw32/4.6.2/../../../../include/windef.h:52:0: note: this is the location of the previous definition

which seemed to be caused by the values to TRUE and FALSE being enclosed
in parentheses.

tentec/orion.h

@@ -31,8 +31,8 @@
  * This backend supports the Ten-Tec Orion (565) and Orion II (566) transceivers.
  */
 
-#define TRUE	(1)
-#define FALSE	(0)
+#define TRUE	1
+#define FALSE	0
 #define TT565_BUFSIZE 16
 
 /**