qemu-log: Allow usage in libhw

Add #ifdef to avoid complaint about use of poisoned "env".
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>
Signed-off-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NEdgar E. Iglesias <edgar.iglesias@gmail.com>

qemu-log.h

@@ -50,6 +50,7 @@ extern int loglevel;
 
 /* Special cases: */
 
+#ifdef NEED_CPU_H
 /* cpu_dump_state() logging functions: */
 #define log_cpu_state(env, f) cpu_dump_state((env), logfile, fprintf, (f));
 #define log_cpu_state_mask(b, env, f) do {           \
@@ -64,6 +65,7 @@ extern int loglevel;
 
 /* page_dump() output to the log file: */
 #define log_page_dump() page_dump(logfile)
+#endif