sparc64: clear syscall_noerror on the entry to syscall, not on the exit

Move that sucker to just before TI_FPDEPTH and replace stb with sth in
etrap_save().  Take current_ds to its old place, so that we don't push
wsaved into TI_... flags.  That allows to lose clearing syscall_noerror
on return from syscall.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 9e28a11..85be1ca 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -624,7 +624,7 @@
 void prom_world(int enter)
 {
 	if (!enter)
-		set_fs((mm_segment_t) { get_thread_current_ds() });
+		set_fs(get_fs());
 
 	__asm__ __volatile__("flushw");
 }