libc: ARM: update syscalls with new script

Used the new gensyscalls.py script to update the ARM syscalls with the
BEGIN(x) and END(x) macros to give size information for the code of the
syscall. Useful for valgrind.

Change-Id: I8c481c8928401ac110fd19b087f7d67e4db39326
diff --git a/libc/arch-arm/syscalls/sigaltstack.S b/libc/arch-arm/syscalls/sigaltstack.S
index 3625d0b..b541a87 100644
--- a/libc/arch-arm/syscalls/sigaltstack.S
+++ b/libc/arch-arm/syscalls/sigaltstack.S
@@ -1,13 +1,8 @@
 /* autogenerated by gensyscalls.py */
+#include <machine/asm.h>
 #include <sys/linux-syscalls.h>
 
-    .text
-    .type sigaltstack, #function
-    .globl sigaltstack
-    .align 4
-    .fnstart
-
-sigaltstack:
+ENTRY(sigaltstack)
     .save   {r4, r7}
     stmfd   sp!, {r4, r7}
     ldr     r7, =__NR_sigaltstack
@@ -16,4 +11,4 @@
     movs    r0, r0
     bxpl    lr
     b       __set_syscall_errno
-    .fnend
+END(sigaltstack)