sparc_brk() is not needed anymore

the checks it's doing are duplicated in sys_brk() and failing
them early makes no sense, AFAICT.

Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/sparc/kernel/systbls.h

@@ -9,7 +9,6 @@
 struct new_utsname;
 
 extern asmlinkage unsigned long sys_getpagesize(void);
-extern asmlinkage unsigned long sparc_brk(unsigned long brk);
 extern asmlinkage long sparc_pipe(struct pt_regs *regs);
 extern asmlinkage long sys_ipc(unsigned int call, int first,
 			       unsigned long second,