crypto: ecdh - fix 'ecdh_init'

mainline inclusion
from mainline-master
commit 8fd28fa5
category: bugfix
bugzilla: 173981
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8fd28fa5046b377039d5bbc0ab2f625dec703980



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NIST P192 is not unregistered if failed to register NIST P256,
actually it need to unregister the algorithms already registered.

Signed-off-by: Hui Tang <tanghui20@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Mingqiang Ling <lingmingqiang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>