net/core: remove redundant sk_callback_lock initialization

sk_callback_lock has already been initialized in sk_init_common().

Signed-off-by: Gou Hao <gouhao@uniontech.com>
Reviewed-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20240526145718.9542-1-gouhao@uniontech.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>