There are no PC98 amd64 machines, so gc a few stray ifdefs.

sys/amd64/amd64/prof_machdep.c

@@ -49,11 +49,7 @@ __FBSDID("$FreeBSD$");
 
 #include <machine/asmacros.h>
 
-#ifdef PC98
-#include <pc98/pc98/pc98.h>
-#else
 #include <i386/isa/isa.h>
-#endif
 #include <i386/isa/timerreg.h>
 
 #ifdef GUPROF

sys/amd64/isa/atpic.c

@@ -64,14 +64,9 @@ __FBSDID("$FreeBSD$");
 #define	SLAVE	1
 
 /*
- * PC-98 machines wire the slave 8259A to pin 7 on the master PIC, and
  * PC-AT machines wire the slave PIC to pin 2 on the master PIC.
  */
-#ifdef PC98
-#define	ICU_SLAVEID	7
-#else
 #define	ICU_SLAVEID	2
-#endif
 
 /*
  * Determine the base master and slave modes not including auto EOI support.