Removed trailing spaces in the most relevant files

Command used for the job:
egrep -rl ' $' --include *.c --include *.h --include  *.s --include  *.inc --include  *.txt *  | xargs sed -i 's/\s\+$//g'

Credits to Grant Murphy from Stack Overflow.

include/constants/battle_frontier_trainers.h

@@ -2,7 +2,7 @@
 #define GUARD_CONSTANTS_BATTLE_FRONTIER_TRAINERS_H
 
 #define FRONTIER_TRAINER_BRADY          0
-#define FRONTIER_TRAINER_CONNER         1    
+#define FRONTIER_TRAINER_CONNER         1
 #define FRONTIER_TRAINER_BRADLEY        2
 #define FRONTIER_TRAINER_CYBIL          3
 #define FRONTIER_TRAINER_RODETTE        4