Make gensyscalls.py use the ALIAS_SYMBOL macro.

Change-Id: Ib94c0abb6fc85126ecc5ed3f1962b2b8b90b9952
diff --git a/libc/arch-mips/syscalls/fstat64.S b/libc/arch-mips/syscalls/fstat64.S
index 525c23c..16e2791 100644
--- a/libc/arch-mips/syscalls/fstat64.S
+++ b/libc/arch-mips/syscalls/fstat64.S
@@ -18,5 +18,4 @@
     .set reorder
 END(fstat64)
 
-    .globl fstat
-    .equ fstat, fstat64
+ALIAS_SYMBOL(fstat, fstat64)