serial: 8250: omap: convert to modern PM ops

The new uart_write() function is only called from suspend/resume code, causing
a build warning when those are left out:

drivers/tty/serial/8250/8250_omap.c:169:13: error: 'uart_write' defined but not used [-Werror=unused-function]

Remove the #ifdefs and use the modern pm_ops/pm_sleep_ops and their wrappers
to let the compiler see where it's used but still drop the dead code.

Fixes: 398cecc ("serial: 8250: omap: Fix imprecise external abort for omap_8250_pm()")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20230517202012.634386-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_omap.c

@@ -1595,7 +1595,6 @@ static int omap8250_remove(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
 static int omap8250_prepare(struct device *dev)
 {
 	struct omap8250_priv *priv = dev_get_drvdata(dev);
@@ -1640,12 +1639,7 @@ static int omap8250_resume(struct device *dev)
 	serial8250_resume_port(priv->line);
 	return 0;
 }
-#else
-#define omap8250_prepare NULL
-#define omap8250_complete NULL
-#endif
 
-#ifdef CONFIG_PM
 static int omap8250_lost_context(struct uart_8250_port *up)
 {
 	u32 val;
@@ -1773,7 +1767,6 @@ static int omap8250_runtime_resume(struct device *dev)
 	schedule_work(&priv->qos_work);
 	return 0;
 }
-#endif
 
 #ifdef CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP
 static int __init omap8250_console_fixup(void)
@@ -1816,17 +1809,17 @@ console_initcall(omap8250_console_fixup);
 #endif
 
 static const struct dev_pm_ops omap8250_dev_pm_ops = {
-	SET_SYSTEM_SLEEP_PM_OPS(omap8250_suspend, omap8250_resume)
-	SET_RUNTIME_PM_OPS(omap8250_runtime_suspend,
+	SYSTEM_SLEEP_PM_OPS(omap8250_suspend, omap8250_resume)
+	RUNTIME_PM_OPS(omap8250_runtime_suspend,
 			   omap8250_runtime_resume, NULL)
-	.prepare        = omap8250_prepare,
-	.complete       = omap8250_complete,
+	.prepare        = pm_sleep_ptr(omap8250_prepare),
+	.complete       = pm_sleep_ptr(omap8250_complete),
 };
 
 static struct platform_driver omap8250_platform_driver = {
 	.driver = {
 		.name		= "omap8250",
-		.pm		= &omap8250_dev_pm_ops,
+		.pm		= pm_ptr(&omap8250_dev_pm_ops),
 		.of_match_table = omap8250_dt_ids,
 	},
 	.probe			= omap8250_probe,