serial: 8250: dw: Move the IO accessors to 8250_dwlib.h

These accessors should be used instead of the regular readl/writel()
helpers. In order to use them also from 8250_dw.c in this directory,
move the helpers to 8250_dwlib.h

There is no functional change.

There is no need for declaring `struct uart_port` or even UPIO_MEM32BE
which both are already included in the 8250_dwlib.h header by 8250.h.
Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220422180615.9098-8-miquel.raynal@bootlin.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_dwlib.c

@@ -3,7 +3,6 @@
 
 #include <linux/bitops.h>
 #include <linux/device.h>
-#include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/serial_8250.h>
 #include <linux/serial_core.h>
@@ -32,21 +31,6 @@
 /* Helper for FIFO size calculation */
 #define DW_UART_CPR_FIFO_SIZE(a)	(((a >> 16) & 0xff) * 16)
 
-static inline u32 dw8250_readl_ext(struct uart_port *p, int offset)
-{
-	if (p->iotype == UPIO_MEM32BE)
-		return ioread32be(p->membase + offset);
-	return readl(p->membase + offset);
-}
-
-static inline void dw8250_writel_ext(struct uart_port *p, int offset, u32 reg)
-{
-	if (p->iotype == UPIO_MEM32BE)
-		iowrite32be(reg, p->membase + offset);
-	else
-		writel(reg, p->membase + offset);
-}
-
 /*
  * divisor = div(I) + div(F)
  * "I" means integer, "F" means fractional

drivers/tty/serial/8250/8250_dwlib.h

 /* SPDX-License-Identifier: GPL-2.0+ */
 /* Synopsys DesignWare 8250 library header file. */
 
+#include <linux/io.h>
 #include <linux/notifier.h>
 #include <linux/types.h>
 #include <linux/workqueue.h>
@@ -50,3 +51,18 @@ static inline struct dw8250_data *to_dw8250_data(struct dw8250_port_data *data)
 {
 	return container_of(data, struct dw8250_data, data);
 }
+
+static inline u32 dw8250_readl_ext(struct uart_port *p, int offset)
+{
+	if (p->iotype == UPIO_MEM32BE)
+		return ioread32be(p->membase + offset);
+	return readl(p->membase + offset);
+}
+
+static inline void dw8250_writel_ext(struct uart_port *p, int offset, u32 reg)
+{
+	if (p->iotype == UPIO_MEM32BE)
+		iowrite32be(reg, p->membase + offset);
+	else
+		writel(reg, p->membase + offset);
+}