net: Remove unused inline function dst_hold_and_use()

stable inclusion
from stable-v5.10.185
commit 7d07fd03f50c2048abe4c45719630de3b9613c46
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8L5XP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7d07fd03f50c2048abe4c45719630de3b9613c46



--------------------------------

commit 0b81882d upstream.

All uses of dst_hold_and_use() have
been removed since commit 1202cdd6 ("Remove DECnet support
from kernel"), so remove it.

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>