softmmu: introduce cpu_ldst.h

This will collect all load and store helpers soon.  For now
it is just a replacement for softmmu_exec.h, which this patch
stops including directly, but we also include it where this will
be necessary in order to simplify the next patch.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/monitor.c b/monitor.c
index 593679a..0565816 100644
--- a/monitor.c
+++ b/monitor.c
@@ -66,6 +66,7 @@
 #include "trace/simple.h"
 #endif
 #include "exec/memory.h"
+#include "exec/cpu_ldst.h"
 #include "qmp-commands.h"
 #include "hmp.h"
 #include "qemu/thread.h"