kfifo: don't use "proxy" headers

Update header inclusions to follow IWYU (Include What You Use) principle.

Link: https://lkml.kernel.org/r/20240423192529.3249134-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alain Volmat <alain.volmat@foss.st.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Jernej Skrabec <jernej.skrabec@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Samuel Holland <samuel@sholland.org>
Cc: Sean Wang <sean.wang@mediatek.com>
Cc: Sean Young <sean@mess.org>
Cc: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/kfifo.h

@@ -36,10 +36,15 @@
  * to lock the reader.
  */
 
-#include <linux/kernel.h>
+#include <linux/array_size.h>
 #include <linux/spinlock.h>
 #include <linux/stddef.h>
-#include <linux/scatterlist.h>
+#include <linux/types.h>
+
+#include <asm/barrier.h>
+#include <asm/errno.h>
+
+struct scatterlist;
 
 struct __kfifo {
 	unsigned int	in;

lib/kfifo.c

@@ -5,13 +5,13 @@
  * Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net>
  */
 
-#include <linux/kernel.h>
-#include <linux/export.h>
-#include <linux/slab.h>
 #include <linux/err.h>
-#include <linux/log2.h>
-#include <linux/uaccess.h>
+#include <linux/export.h>
 #include <linux/kfifo.h>
+#include <linux/log2.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
 
 /*
  * internal helper to calculate the unused elements in a fifo

samples/kfifo/dma-example.c

@@ -6,8 +6,9 @@
  */
 
 #include <linux/init.h>
-#include <linux/module.h>
 #include <linux/kfifo.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
 
 /*
  * This module shows how to handle fifo dma operations.