Added RIG_FUNC_NB2

From FT-950 CAT manual, there are two NB options:

NB P1 P2 ;
P1 0: Fixed
P2 0: Noise Blanker “OFF”
1: Noise Blanker “ON”
2: Noise Blanker (Wide) “ON”

rigs/yaesu/ft950.h

@@ -64,7 +64,7 @@
                RIG_LEVEL_BAND_SELECT)
 
 #define FT950_FUNCS (RIG_FUNC_TONE|RIG_FUNC_TSQL|RIG_FUNC_LOCK|\
-               RIG_FUNC_MON|RIG_FUNC_NB|RIG_FUNC_NR|RIG_FUNC_VOX|\
+               RIG_FUNC_MON|RIG_FUNC_NB|RIG_FUNC_NB2|RIG_FUNC_NR|RIG_FUNC_VOX|\
                RIG_FUNC_FBKIN|RIG_FUNC_COMP|RIG_FUNC_ANF|RIG_FUNC_MN|\
                RIG_FUNC_RIT|RIG_FUNC_XIT|\
                RIG_FUNC_TUNER)