Add missing PTRACE_SETVFPREGS.

Change-Id: I070903ea7ceb90a3ff54fbae09c0ac70a7af1e3d
diff --git a/libc/kernel/arch-arm/asm/ptrace.h b/libc/kernel/arch-arm/asm/ptrace.h
index b6be08c..3faf738 100644
--- a/libc/kernel/arch-arm/asm/ptrace.h
+++ b/libc/kernel/arch-arm/asm/ptrace.h
@@ -30,6 +30,7 @@
 #define PTRACE_SETCRUNCHREGS 26
 
 #define PTRACE_GETVFPREGS 27
+#define PTRACE_SETVFPREGS 28
 
 #define USR26_MODE 0x00000000
 #define FIQ26_MODE 0x00000001