headers_check fix: x86, swab.h

fix the following 'make headers_check' warnings:

  usr/include/asm/swab.h:4: include of <linux/types.h> is preferred over <asm/types.h>
  usr/include/asm/swab.h:7: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>

arch/x86/include/asm/swab.h

 #ifndef _ASM_X86_SWAB_H
 #define _ASM_X86_SWAB_H
 
-#include <asm/types.h>
+#include <linux/types.h>
 #include <linux/compiler.h>
 
 static inline __attribute_const__ __u32 __arch_swab32(__u32 val)