xtensa: we don't need to include asm/io.h

Remove include statement to include asm/io.h.
Signed-off-by: NChris Zankel <chris@zankel.net>

arch/xtensa/platforms/xt2000/include/platform/hardware.h

@@ -16,7 +16,6 @@
 #define _XTENSA_XT2000_HARDWARE_H
 
 #include <variant/core.h>
-#include <asm/io.h>
 
 /* 
  * Memory configuration.