crypto: ecrdsa - Fix incorrect use of vli_cmp

Correctly compare values that shall be greater-or-equal and not just
greater.

Fixes: 0d7a7864 ("crypto: ecrdsa - add EC-RDSA (GOST 34.10) algorithm")
Cc: <stable@vger.kernel.org>
Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>