s390/bp: remove s390_isolate_bp_guest()

s390_isolate_bp_guest() is unused. Remove it.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/include/asm/processor.h

@@ -329,8 +329,6 @@ static __always_inline void __noreturn disabled_wait(void)
 
 #define ARCH_LOW_ADDRESS_LIMIT	0x7fffffffUL
 
-extern int s390_isolate_bp_guest(void);
-
 static __always_inline bool regs_irqs_disabled(struct pt_regs *regs)
 {
 	return arch_irqs_disabled_flags(regs->psw.mask);

arch/s390/kernel/processor.c

@@ -364,12 +364,3 @@ const struct seq_operations cpuinfo_op = {
 	.stop	= c_stop,
 	.show	= show_cpuinfo,
 };
-
-int s390_isolate_bp_guest(void)
-{
-	if (!test_facility(82))
-		return -EOPNOTSUPP;
-	set_thread_flag(TIF_ISOLATE_BP_GUEST);
-	return 0;
-}
-EXPORT_SYMBOL(s390_isolate_bp_guest);