Fix regression in ASN1_UTCTIME_cmp_time_t

Previously, ASN1_UTCTIME_cmp_time_t would return 1 if s > t, -1 if
s < t, and 0 if s == t.

This behavior was broken in a refactor [0], resulting in the opposite
time comparison behavior.

[0]: 904348a4



PR#3706

Reviewed-by: Stephen Henson <steve@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>