migration: Don't use *_to_cpup() and cpu_to_*w()

The *_to_cpup() and cpu_to_*w() functions just compose a pointer
dereference with a byteswap. Instead use ld*_p() and st*_p(),
which handle potential pointer misalignment and avoid the need
to cast the pointer.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Message-Id: <1465574962-2710-1-git-send-email-peter.maydell@linaro.org>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
diff --git a/migration/savevm.c b/migration/savevm.c
index ae2ef8b..6da084c 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -823,9 +823,9 @@
     buf[tmplen++] = '\0';
 
     for (t = 0; t < len; t++) {
-        cpu_to_be64w((uint64_t *)(buf + tmplen), start_list[t]);
+        stq_be_p(buf + tmplen, start_list[t]);
         tmplen += 8;
-        cpu_to_be64w((uint64_t *)(buf + tmplen), length_list[t]);
+        stq_be_p(buf + tmplen, length_list[t]);
         tmplen += 8;
     }
     qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RAM_DISCARD, tmplen, buf);