[S390] remove export of sys_call_table

Remove export of the sys_call_table symbol to prevent the misuse of it.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/entry.S

@@ -1019,7 +1019,6 @@ cleanup_io_leave_insn:
                .long  cleanup_critical
 
 #define SYSCALL(esa,esame,emu)	.long esa
-	.globl  sys_call_table
 sys_call_table:
 #include "syscalls.S"
 #undef SYSCALL

arch/s390/kernel/entry64.S

@@ -993,7 +993,6 @@ cleanup_io_leave_insn:
                .quad  __critical_end
 
 #define SYSCALL(esa,esame,emu)	.long esame
-	.globl  sys_call_table
 sys_call_table:
 #include "syscalls.S"
 #undef SYSCALL
@@ -1001,7 +1000,6 @@ sys_call_table:
 #ifdef CONFIG_COMPAT
 
 #define SYSCALL(esa,esame,emu)	.long emu
-	.globl  sys_call_table_emu
 sys_call_table_emu:
 #include "syscalls.S"
 #undef SYSCALL