Add cfi directives to x86 syscalls.

Modify the syscalls script to generate the cfi directives for x86
syscalls.

Update the x86 syscalls.

Change-Id: Ia1993dc714a7e79f917087fff8200e9a02c52603

libc/arch-x86/syscalls/madvise.S

@@ -6,6 +6,10 @@ ENTRY(madvise)
     pushl   %ebx
     pushl   %ecx
     pushl   %edx
+    .cfi_def_cfa_offset 12
+    .cfi_rel_offset ebx, 0
+    .cfi_rel_offset ecx, 4
+    .cfi_rel_offset edx, 8
     mov     16(%esp), %ebx
     mov     20(%esp), %ecx
     mov     24(%esp), %edx