OMAP: UART: don't do automatic bus-level suspend/resume

Since the omap_device for UART is currently managed inside the idle
path itself,  don't let the bus-level code suspend/resume the UART.

To prevent this, pm_runtime_get() is used when preparing for suspend
and pm_runtime_put() is used when finished with suspend.
Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

arch/arm/mach-omap2/serial.c

@@ -26,6 +26,7 @@
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/serial_8250.h>
+#include <linux/pm_runtime.h>
 
 #ifdef CONFIG_SERIAL_OMAP
 #include <plat/omap-serial.h>
@@ -530,15 +531,18 @@ void omap_uart_enable_irqs(int enable)
 	struct omap_uart_state *uart;
 
 	list_for_each_entry(uart, &uart_list, node) {
-		if (enable)
+		if (enable) {
+			pm_runtime_put_sync(&uart->pdev->dev);
 			ret = request_threaded_irq(uart->irq, NULL,
 						   omap_uart_interrupt,
 						   IRQF_SHARED,
 						   "serial idle",
 						   (void *)uart);
-		else
+		} else {
+			pm_runtime_get_noresume(&uart->pdev->dev);
 			free_irq(uart->irq, (void *)uart);
 		}
+	}
 }
 
 static ssize_t sleep_timeout_show(struct device *dev,