[Patch] uml: fix one compile error

["Américo Wang" <xiyou.wangcong@gmail.com>]

This patch fixed the following compile error:

  CC      arch/um/sys-i386/signal.o
  /home/wangcong/Projects/linux-2.6/arch/um/sys-i386/signal.c: In
function 'copy_sc_from_user':
/home/wangcong/Projects/linux-2.6/arch/um/sys-i386/signal.c:182:
warning: dereferencing 'void *' pointer
/home/wangcong/Projects/linux-2.6/arch/um/sys-i386/signal.c:182:
error: request for member '_fxsr_env' in something not a structure or
union


Signed-off-by: WANG Cong <wangcong@zeuux.org>
Cc: jdike@addtoit.com

---
diff --git a/arch/um/sys-i386/signal.c b/arch/um/sys-i386/signal.c
index fd0c25a..1296473 100644
--- a/arch/um/sys-i386/signal.c
+++ b/arch/um/sys-i386/signal.c
@@ -179,7 +179,8 @@ static int copy_sc_from_user(struct pt_regs *regs,
 	if (have_fpx_regs) {
 		struct user_fxsr_struct fpx;
 
-		err = copy_from_user(&fpx, &sc.fpstate->_fxsr_env[0],
+		err = copy_from_user(&fpx,
+			&((struct _fpstate __user *)sc.fpstate)->_fxsr_env[0],
 				     sizeof(struct user_fxsr_struct));
 		if (err)
 			return 1;