UPSTREAM: wireguard: main: remove unused include <linux/version.h>

Remove <linux/version.h> from the includes for main.c, which is unused.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
[Jason: reworded commit message]
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 43967b6ff91e53bcce5ae08c16a0588a475b53a1)
Bug: 152722841
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I5ee6cedcb037dbe522ab50dcc5b7c66f06d76b16