sys/crypto/openssl: update powerpc* ASM

This change updates the crypto powerpc* ASM via the prescribed process
documented in crypto/openssl/FREEBSD-upgrade.

This change syncs the ASM with 3.0.15's generated ASM.

MFC after: 1 week
MFC with: a7148ab39c03abd4d1a84997c70bf96f15dd2a09
MFC with: cc717b574d7faa2e0b2de1a985076286cef74187
Differential Revision: https://reviews.freebsd.org/D46604