[SPARC64]: Kill _exit kernelsyscall stub from unistd.h

include/asm-sparc64/unistd.h

@@ -446,7 +446,6 @@ static __inline__ _syscall1(int,dup,int,fd)
 static __inline__ _syscall3(int,execve,__const__ char *,file,char **,argv,char **,envp)
 static __inline__ _syscall3(int,open,__const__ char *,file,int,flag,int,mode)
 static __inline__ _syscall1(int,close,int,fd)
-static __inline__ _syscall1(int,_exit,int,exitcode)
 static __inline__ _syscall3(pid_t,waitpid,pid_t,pid,int *,wait_stat,int,options)
 
 #include <linux/linkage.h>