Ensure syscall functions are consistently prefixed with "NaClSys"

src/trusted/service_runtime/arch/arm/nacl_text_pad_test.S

 /*
  * Copyright (c) 2011 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "native_client/src/include/arm_sandbox.h"
 #include "native_client/src/trusted/service_runtime/include/bits/nacl_syscalls.h"
 #include "native_client/src/trusted/service_runtime/nacl_config.h"
 
 /* the macros below are used with movw/movt and absolute values */
@@ skipping 126 matching lines @@
         movt r1, :upper16:(end_of_text)
         mov r0, #1
         bl write_num_16
 
         mov r0, #1
         mov r1, #'\n'
         nop
         bl write_char
 
         mov r0, #0
-        movw r3, lower_16(NACL_SYSCALL_ADDR(NACL_sys_sysbrk))
-        movt r3, upper_16(NACL_SYSCALL_ADDR(NACL_sys_sysbrk))
+        movw r3, lower_16(NACL_SYSCALL_ADDR(NACL_sys_brk))
+        movt r3, upper_16(NACL_SYSCALL_ADDR(NACL_sys_brk))
         nop
 
         nop
         nop
         bic r3, r3, #0xc000000f
         blx r3
 
         mov r4, r0  /* save a copy of break addr */
         mov r1, r0
         mov r0, #1
@@ skipping 77 matching lines @@
               NACL_INSTR_ARM_HALT_FILL
 #endif
 
 end_of_text:
 
 #if defined(EXPECTED_RODATA)
         .section .rodata
 ro_str: .ascii "Hello world\n"
         /*      123456789012 */
 #endif