debug.h: merge both instances into ihk/debug.h

We do not need two debug.h files.

Take Fujitsu's STATIC_ASSERT over BUILD_BUG_ON because it is more used

Change-Id: If04c17fbb7406ab15fe86267fed8d6da460cec62
Fujitsu: POSTK_DEBUG_ARCH_DEP_9

arch/x86_64/kernel/perfctr.c

@@ -12,12 +12,11 @@
 #include <march.h>
 #include <errno.h>
 #include <cls.h>
-#include <ihk/debug.h>
 #include <ihk/cpu.h>
 #include <registers.h>
 #include <mc_perf_event.h>
 #include <config.h>
-#include <debug.h>
+#include <ihk/debug.h>
 
 extern unsigned int *x86_march_perfmap;
 extern int running_on_kvm(void);