mfd: intel-lpss: Use MODULE_SOFTDEP() instead of implicit request

There is no need to handle optional module request in the driver
when user space tools has that feature for ages.

Replace custom code by MODULE_SOFTDEP() macro to let user space know
that we would like to have the DMA driver loaded first, if any.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/intel-lpss.c

@@ -128,17 +128,6 @@ static const struct mfd_cell intel_lpss_spi_cell = {
 static DEFINE_IDA(intel_lpss_devid_ida);
 static struct dentry *intel_lpss_debugfs;
 
-static int intel_lpss_request_dma_module(const char *name)
-{
-	static bool intel_lpss_dma_requested;
-
-	if (intel_lpss_dma_requested)
-		return 0;
-
-	intel_lpss_dma_requested = true;
-	return request_module("%s", name);
-}
-
 static void intel_lpss_cache_ltr(struct intel_lpss *lpss)
 {
 	lpss->active_ltr = readl(lpss->priv + LPSS_PRIV_ACTIVELTR);
@@ -429,16 +418,6 @@ int intel_lpss_probe(struct device *dev,
 		dev_warn(dev, "Failed to create debugfs entries\n");
 
 	if (intel_lpss_has_idma(lpss)) {
-		/*
-		 * Ensure the DMA driver is loaded before the host
-		 * controller device appears, so that the host controller
-		 * driver can request its DMA channels as early as
-		 * possible.
-		 *
-		 * If the DMA module is not there that's OK as well.
-		 */
-		intel_lpss_request_dma_module(LPSS_IDMA64_DRIVER_NAME);
-
 		ret = mfd_add_devices(dev, lpss->devid, &intel_lpss_idma64_cell,
 				      1, info->mem, info->irq, NULL);
 		if (ret)
@@ -554,3 +533,11 @@ MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
 MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@linux.intel.com>");
 MODULE_DESCRIPTION("Intel LPSS core driver");
 MODULE_LICENSE("GPL v2");
+/*
+ * Ensure the DMA driver is loaded before the host controller device appears,
+ * so that the host controller driver can request its DMA channels as early
+ * as possible.
+ *
+ * If the DMA module is not there that's OK as well.
+ */
+MODULE_SOFTDEP("pre: platform:" LPSS_IDMA64_DRIVER_NAME);