Make mips/mips64 syscall stubs more like the other architectures.

Change-Id: I55f8c1a95f643a6e484f12fbcc25e2c77e55b6b8
diff --git a/libc/arch-mips/syscalls/sigaltstack.S b/libc/arch-mips/syscalls/sigaltstack.S
index cd8538b..6632164 100644
--- a/libc/arch-mips/syscalls/sigaltstack.S
+++ b/libc/arch-mips/syscalls/sigaltstack.S
@@ -1,14 +1,8 @@
 /* Generated by gensyscalls.py. Do not edit. */
 
-#include <asm/unistd.h>
-#include <machine/asm.h>
-#include <machine/regdef.h>
-    .text
-    .globl sigaltstack
-    .align 4
-    .ent sigaltstack
+#include <private/bionic_asm.h>
 
-sigaltstack:
+ENTRY(sigaltstack)
     .set noreorder
     .cpload t9
     li v0, __NR_sigaltstack
@@ -22,4 +16,4 @@
     j t9
     nop
     .set reorder
-    .end sigaltstack
+END(sigaltstack)