phonet/pep: Move call to pn_skb_get_dst_sockaddr() earlier in pep_sock_accept()

A new warning in clang [1] points out a place in pep_sock_accept() where
dst is uninitialized then passed as a const pointer to pep_find_pipe():

  net/phonet/pep.c:829:37: error: variable 'dst' is uninitialized when passed as a const pointer argument here [-Werror,-Wuninitialized-const-pointer]
    829 |         newsk = pep_find_pipe(&pn->hlist, &dst, pipe_handle);
        |                                            ^~~:

Move the call to pn_skb_get_dst_sockaddr(), which initializes dst, to
before the call to pep_find_pipe(), so that dst is consistently used
initialized throughout the function.

Cc: [email protected]
Fixes: f7ae8d5 ("Phonet: allocate sock from accept syscall rather than soft IRQ")
Link: llvm/llvm-project@00dacf8 [1]
Closes: ClangBuiltLinux/linux#2101
Signed-off-by: Nathan Chancellor <[email protected]>
Link: https://patch.msgid.link/20250715-net-phonet-fix-uninit-const-pointer-v1-1-8efd1bd188b3@kernel.org
Signed-off-by: Jakub Kicinski <[email protected]>

Author: nathanchance

net/phonet/pep.c

@@ -826,6 +826,7 @@ static struct sock *pep_sock_accept(struct sock *sk,
 	}
 
 	/* Check for duplicate pipe handle */
+	pn_skb_get_dst_sockaddr(skb, &dst);
 	newsk = pep_find_pipe(&pn->hlist, &dst, pipe_handle);
 	if (unlikely(newsk)) {
 		__sock_put(newsk);
@@ -850,7 +851,6 @@ static struct sock *pep_sock_accept(struct sock *sk,
 	newsk->sk_destruct = pipe_destruct;
 
 	newpn = pep_sk(newsk);
-	pn_skb_get_dst_sockaddr(skb, &dst);
 	pn_skb_get_src_sockaddr(skb, &src);
 	newpn->pn_sk.sobject = pn_sockaddr_get_object(&dst);
 	newpn->pn_sk.dobject = pn_sockaddr_get_object(&src);