milkymist-minimac2: Fix minimac2_read/_write tracepoints

Broken in milkymist-minimac.c from the start (commit 07424544),
faithfully moved to milkymist-minimac2.c (commit 57aa265d).
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

hw/net/milkymist-minimac2.c

@@ -355,7 +355,7 @@ minimac2_write(void *opaque, hwaddr addr, uint64_t value,
 {
     MilkymistMinimac2State *s = opaque;
 
-    trace_milkymist_minimac2_memory_read(addr, value);
+    trace_milkymist_minimac2_memory_write(addr, value);
 
     addr >>= 2;
     switch (addr) {