headers_check fix: xtensa, swab.h

fix the following 'make headers_check' warnings:

  usr/include/asm-xtensa/swab.h:14: include of <linux/types.h> is preferred over <asm/types.h>
  usr/include/asm-xtensa/swab.h:19: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>

arch/xtensa/include/asm/swab.h

@@ -11,7 +11,7 @@
 #ifndef _XTENSA_SWAB_H
 #define _XTENSA_SWAB_H
 
-#include <asm/types.h>
+#include <linux/types.h>
 #include <linux/compiler.h>
 
 #define __SWAB_64_THRU_32__