vsock: Make accept()ed sockets use custom setsockopt()

vsock: Make accept()ed sockets use custom setsockopt()

[ Upstream commit ce5e612dd411de096aa041b9e9325ba1bec5f9f4 ]

SO_ZEROCOPY handling in vsock_connectible_setsockopt() does not get called
on accept()ed sockets due to a missing flag. Flip it.

Fixes: e0718bd82e27 ("vsock: enable setting SO_ZEROCOPY")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Link: https://patch.msgid.link/20251229-vsock-child-sock-custom-sockopt-v2-1-64778d6c4f88@rbox.co
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>