kernel-build-tools: Explicitly build libcrypto

libcrypto had been so far built indirectly referred to by another
target. That dependency apparently got dropped.

Hence, explicitly built libcrypto for distribution.

Bug: 135570712
Signed-off-by: Matthias Maennich <maennich@google.com>
Change-Id: I84739f9f1814325cfe356ddbce503dcea315fb23