sparc64: Fix sparse warnings in fault.c

1) set_brkpt() is referenced by nothing and hasn't been used by anyone
   to my knowledge for many many years.  So just delete it.

2) add extern decl for do_sparc64_fault() in asm/pgtable_64.h

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index bb9ec2c..b049abf 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -770,6 +770,8 @@
 
 extern unsigned long cmdline_memory_size;
 
+extern asmlinkage void do_sparc64_fault(struct pt_regs *regs);
+
 #endif /* !(__ASSEMBLY__) */
 
 #endif /* !(_SPARC64_PGTABLE_H) */