xfrm: compat: change expression for switch in xfrm_xlate64

Compare XFRM_MSG_NEWSPDINFO (value from netlink
configuration messages enum) with nlh_src->nlmsg_type
instead of nlh_src->nlmsg_type - XFRM_MSG_BASE.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 4e950506

 ("net/xfrm/compat: Copy xfrm_spdattr_type_t atributes")
Signed-off-by: Anastasia Belova <abelova@astralinux.ru>
Acked-by: Dmitry Safonov <0x7f454c46@gmail.com>
Tested-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>