crypto/ppccap.c: Fix which hwcap value used to check for HWCAP_ARCH_3_00

CLA: trivial

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/8889)

(cherry picked from commit 99592c73)