headers_check fix: blackfin, swab.h

fix the following 'make headers_check' warnings:

  usr/include/asm-blackfin/swab.h:4: include of <linux/types.h> is preferred over <asm/types.h>
  usr/include/asm-blackfin/swab.h:13: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>

arch/blackfin/include/asm/swab.h

 #ifndef _BLACKFIN_SWAB_H
 #define _BLACKFIN_SWAB_H
 
-#include <asm/types.h>
+#include <linux/types.h>
 #include <linux/compiler.h>
 
 #if defined(__GNUC__) && !defined(__STRICT_ANSI__) || defined(__KERNEL__)