treewide: Remove uninitialized_var() usage

commit 3f649ab728cda8038259d8f14492fe400fbab911 upstream.

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/[email protected]/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <[email protected]> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <[email protected]> # IB
Acked-by: Kalle Valo <[email protected]> # wireless drivers
Reviewed-by: Chao Yu <[email protected]> # erofs
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

net/sunrpc/xprtsock.c

@@ -496,8 +496,8 @@ xs_read_stream_request(struct sock_xprt *transport, struct msghdr *msg,
 		int flags, struct rpc_rqst *req)
 {
 	struct xdr_buf *buf = &req->rq_private_buf;
-	size_t want, uninitialized_var(read);
-	ssize_t uninitialized_var(ret);
+	size_t want, read;
+	ssize_t ret;
 
 	xs_read_header(transport, buf);