chacha20-ppc: do not generate p9 code when target attr unavailable
* cipher/chacha20-ppc.c (HAVE_FUNC_ATTR_TARGET): New. (_gcry_chacha20_ppc9_blocks1, _gcry_chacha20_ppc9_blocks4) (_gcry_chacha20_poly1305_ppc8_blocks4): Use inline functions only if HAVE_FUNC_ATTR_TARGET is defined.
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>