arch/i386/* fs/* ipc/*: mark variables with uninitialized_var()

Mark variables with uninitialized_var() if such a warning appears,
and analysis proves that the var is initialized properly on all paths
it is used.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index f04c7aa..004c2ab 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1867,7 +1867,8 @@
 	loff_t pos;
 	const struct iovec *cur_iov = iov;
 	struct page *user_page, *page;
-	char *buf, *dst;
+	char * uninitialized_var(buf);
+	char *dst;
 	void *fsdata;
 
 	/*