arm/restorer: fix {,rt_}sigframe typo

sigreturn_prep_fpu_frame is no-op for arm, but I think it's better
to fix it while macro correctly expands in sigframe.c - it
may change in some future.

Cc: Christopher Covington <cov@codeaurora.org>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/arch/arm/include/asm/restorer.h

@@ -126,7 +126,7 @@ struct rt_sigframe {
 #define RT_SIGFRAME_UC(rt_sigframe) (&rt_sigframe->sig.uc)
 #define RT_SIGFRAME_REGIP(rt_sigframe) (rt_sigframe)->sig.uc.uc_mcontext.arm_ip
 #define RT_SIGFRAME_HAS_FPU(rt_sigframe) 1
-#define RT_SIGFRAME_FPU(rt_sigframe) ((struct aux_sigframe *)&sigframe->sig.uc.uc_regspace)->vfp
+#define RT_SIGFRAME_FPU(rt_sigframe) ((struct aux_sigframe *)&rt_sigframe->sig.uc.uc_regspace)->vfp
 
 #define SIGFRAME_OFFSET 0