avx512: [SNOW3G] fix direct API
SNOW3G-UEA2 has no AVX512 implementation through direct API,
but should use AVX2 implementation instead.
However, since AVX2 was not defined in snow3g_avx2.c, only AVX
code was being executed.
#define CLEAR_SCRATCH_SIMD_REGS clear_scratch_xmms_avx
#else
#define AVX512
+/* SNOW3G-UEA2 direct functions use up to AVX2 implementations */
+#define AVX2
#define CLEAR_SCRATCH_SIMD_REGS clear_scratch_zmms
#endif
