FIPS202/x86_64: Don't use native x4 backend on x86_64 when not needed

Match the AArch64 behavior and skip the native Keccak-f1600x4 backend
when MLD_CONFIG_SERIAL_FIPS202_ONLY or MLD_CONFIG_REDUCE_RAM is set.

Signed-off-by: Matthias J. Kannwischer <matthias@zerorisc.com>

Author: mkannwischer

mldsa/src/fips202/native/auto.h

@@ -16,7 +16,9 @@
 #include "aarch64/auto.h"
 #endif
 
-#if defined(MLD_SYS_X86_64) && defined(MLD_SYS_X86_64_AVX2)
+#if defined(MLD_SYS_X86_64) && defined(MLD_SYS_X86_64_AVX2) && \
+    !defined(MLD_CONFIG_SERIAL_FIPS202_ONLY) &&                \
+    !defined(MLD_CONFIG_REDUCE_RAM)
 #include "x86_64/xkcp.h"
 #endif