firewire: use in_compat_syscall to check ioctl compatness

Firewire was using is_compat_task to check whether it was in a compat
ioctl or a non-compat ioctl.  Use is_compat_syscall instead so it works
properly on all architectures.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/firewire/core-cdev.c

@@ -221,7 +221,7 @@ struct inbound_phy_packet_event {
 #ifdef CONFIG_COMPAT
 static void __user *u64_to_uptr(u64 value)
 {
-	if (is_compat_task())
+	if (in_compat_syscall())
 		return compat_ptr(value);
 	else
 		return (void __user *)(unsigned long)value;
@@ -229,7 +229,7 @@ static void __user *u64_to_uptr(u64 value)
 
 static u64 uptr_to_u64(void __user *ptr)
 {
-	if (is_compat_task())
+	if (in_compat_syscall())
 		return ptr_to_compat(ptr);
 	else
 		return (u64)(unsigned long)ptr;