x86/irq: Remove duplicated used_vectors definition

Also remove the unparseable comment in the other place while at it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064956.436711634@linutronix.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/desc.h

@@ -483,7 +483,6 @@ static inline void _set_gate(int gate, unsigned type, void *addr,
 				0, 0, __KERNEL_CS);			\
 	} while (0)
 
-/* used_vectors is BITMAP for irq is not managed by percpu vector_irq */
 extern unsigned long used_vectors[];
 
 static inline void alloc_system_vector(int vector)

arch/x86/include/asm/irq.h

@@ -42,9 +42,6 @@ extern bool handle_irq(struct irq_desc *desc, struct pt_regs *regs);
 
 extern __visible unsigned int do_IRQ(struct pt_regs *regs);
 
-/* Interrupt vector management */
-extern DECLARE_BITMAP(used_vectors, NR_VECTORS);
-
 extern void init_ISA_irqs(void);
 
 #ifdef CONFIG_X86_LOCAL_APIC