xtensa: remove wrapper header for asm/device.h

xtensa's asm/device.h is a verbatim copy of asm-generic/device.h and
does not add any arch specific extensions. Thus, use the asm-generic
header directly.
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/include/asm/Kbuild

 generic-y += bug.h
 generic-y += clkdev.h
+generic-y += device.h
 generic-y += div64.h
 generic-y += dma-contiguous.h
 generic-y += emergency-restart.h

arch/xtensa/include/asm/device.h

-/*
- * Arch specific extensions to struct device
- *
- * This file is released under the GPLv2
- */
-#ifndef _ASM_XTENSA_DEVICE_H
-#define _ASM_XTENSA_DEVICE_H
-
-struct dev_archdata {
-};
-
-struct pdev_archdata {
-};
-
-#endif /* _ASM_XTENSA_DEVICE_H */