emulators/ppsspp: unbreak CPUTYPE=nehalem on i386

ext/native/ext/cityhash/city.cpp:569:5: error: use of undeclared identifier '_mm_crc32_u64'

CHUNK(0); PERMUTE3(a, h, c);
^

/wrkdirs/usr/ports/emulators/ppsspp/work/ppsspp-1.6.2/ext/native/ext/cityhash/city.cpp:562:9: note: expanded from macro 'CHUNK'

z = _mm_crc32_u64(z, b + g);                \
    ^