des/asm/des_enc.m4: strip #ifdef OPENSSL_SYS_ULTRASPARC as part of

pre-processor controls cleanup. It doesn't mean that it no longer
works on UltraSPARC, only that it doesn't utilize sparcv9-specific
features like branch prediction hints and load in little-endian byte
order anymore. This "costs" ~3% in EDE3 performance regression on
UltraSPARC.

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Tim Hudson <tjh@openssl.org>