make dkprintf() evaluate its parameters always

Parameters of dkprintf() should be evaluated even if dkprintf() is
disabled.  Because this enables to find expression of parameter obsolete
and to avoid unnecessary compiler warnings such as "unused variable".

arch/x86/kernel/cpu.c

@@ -49,7 +49,7 @@
 #ifdef DEBUG_PRINT_CPU
 #define dkprintf kprintf
 #else
-#define dkprintf(...)
+#define dkprintf(...) do { if (0) kprintf(__VA_ARGS__); } while (0)
 #endif
 
 

arch/x86/kernel/gencore.c

@@ -15,7 +15,7 @@
 #define	dkprintf(...)	kprintf(__VA_ARGS__)
 #define	ekprintf(...)	kprintf(__VA_ARGS__)
 #else
-#define dkprintf(...)
+#define dkprintf(...)	do { if (0) kprintf(__VA_ARGS__); } while (0)
 #define	ekprintf(...)	kprintf(__VA_ARGS__)
 #endif
 

arch/x86/kernel/memory.c

@@ -21,7 +21,7 @@
 #include <process.h>
 #include <page.h>
 
-#define	dkprintf(...)
+#define	dkprintf(...)	do { if (0) kprintf(__VA_ARGS__); } while (0)
 #define	ekprintf(...)	kprintf(__VA_ARGS__)
 
 static char *last_page;

arch/x86/kernel/syscall.c

@@ -34,7 +34,7 @@ long do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact);
 #ifdef DEBUG_PRINT_SC
 #define dkprintf kprintf
 #else
-#define dkprintf(...)
+#define dkprintf(...) do { if (0) kprintf(__VA_ARGS__); } while (0)
 #endif
 
 /*