[S390] fix duplicate export of overflow{ug}id

overflowuid and overflowgid were exported twice.  Remove the export
from s390_ksyms.c

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/s390_ksyms.c

@@ -46,8 +46,6 @@ EXPORT_SYMBOL(__down_interruptible);
  */
 extern int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs);
 EXPORT_SYMBOL(dump_fpu);
-EXPORT_SYMBOL(overflowuid);
-EXPORT_SYMBOL(overflowgid);
 EXPORT_SYMBOL(empty_zero_page);
 
 /*