xtensa: clean up empty include files

Remove empty hw_irq.h and user.h from arch/xtensa/include/asm and use
generic versions instead.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/include/asm/Kbuild

@@ -11,6 +11,7 @@ generic-y += exec.h
 generic-y += extable.h
 generic-y += fb.h
 generic-y += hardirq.h
+generic-y += hw_irq.h
 generic-y += irq_regs.h
 generic-y += irq_work.h
 generic-y += kdebug.h
@@ -30,6 +31,7 @@ generic-y += qspinlock.h
 generic-y += sections.h
 generic-y += topology.h
 generic-y += trace_clock.h
+generic-y += user.h
 generic-y += vga.h
 generic-y += word-at-a-time.h
 generic-y += xor.h

arch/xtensa/include/asm/hw_irq.h

-/*
- * include/asm-xtensa/hw_irq.h
- *
- * This file is subject to the terms and conditions of the GNU General
- * Public License.  See the file "COPYING" in the main directory of
- * this archive for more details.
- *
- * Copyright (C) 2002 - 2005 Tensilica Inc.
- */
-
-#ifndef _XTENSA_HW_IRQ_H
-#define _XTENSA_HW_IRQ_H
-
-#endif

arch/xtensa/include/asm/user.h

-/*
- * include/asm-xtensa/user.h
- *
- * Xtensa Processor version.
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 2001 - 2005 Tensilica Inc.
- */
-
-#ifndef _XTENSA_USER_H
-#define _XTENSA_USER_H
-
-/* This file usually defines a 'struct user' structure. However, it it only
- * used for a.out file, which are not supported on Xtensa.
- */
-
-#endif	/* _XTENSA_USER_H */