s390x/pci: make printf always compile in debug output

Wrapped printf calls inside debug macros (DPRINTF) in `if` statement.
This will ensure that printf function will always compile even if debug
output is turned off and, in turn, will prevent bitrot of the format
strings.

Signed-off-by: Danil Antonov <g.danil.anto@gmail.com>
Message-Id: <CA+KKJYBi31Bs7DtVdzZdwG2t+u5+FGiAhQpd3pqJzUX1O8Cprg@mail.gmail.com>
[CH: remove now misleading comments]
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
index d2a8c0a..f520ce1 100644
--- a/hw/s390x/s390-pci-inst.c
+++ b/hw/s390x/s390-pci-inst.c
@@ -20,15 +20,17 @@
 #include "qemu/error-report.h"
 #include "sysemu/hw_accel.h"
 
-/* #define DEBUG_S390PCI_INST */
-#ifdef DEBUG_S390PCI_INST
-#define DPRINTF(fmt, ...) \
-    do { fprintf(stderr, "s390pci-inst: " fmt, ## __VA_ARGS__); } while (0)
-#else
-#define DPRINTF(fmt, ...) \
-    do { } while (0)
+#ifndef DEBUG_S390PCI_INST
+#define DEBUG_S390PCI_INST  0
 #endif
 
+#define DPRINTF(fmt, ...)                                          \
+    do {                                                           \
+        if (DEBUG_S390PCI_INST) {                                  \
+            fprintf(stderr, "s390pci-inst: " fmt, ## __VA_ARGS__); \
+        }                                                          \
+    } while (0)
+
 static void s390_set_status_code(CPUS390XState *env,
                                  uint8_t r, uint64_t status_code)
 {