dmaengine: dw: append MODULE_ALIAS for platform driver

The commit 9cade1a (dma: dw: split driver to library part and platform
code) introduced a separate platform driver but missed to add a
MODULE_ALIAS("platform:dw_dmac"); to that module.

The patch adds this to get driver loaded automatically if platform device is
registered.

Reported-by: "Blin, Jerome" <jerome.blin@intel.com>
Fixes: 9cade1a (dma: dw: split driver to library part and platform code)
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/dw/platform.c

@@ -26,6 +26,8 @@
 
 #include "internal.h"
 
+#define DRV_NAME "dw_dmac"
+
 static struct dma_chan *dw_dma_of_xlate(struct of_phandle_args *dma_spec,
  struct of_dma *ofdma)
 {
@@ -284,7 +286,7 @@ static struct platform_driver dw_driver = {
  .remove = dw_remove,
  .shutdown = dw_shutdown,
  .driver = {
- .name = "dw_dmac",
+ .name = DRV_NAME,
  .pm = &dw_dev_pm_ops,
  .of_match_table = of_match_ptr(dw_dma_of_id_table),
  .acpi_match_table = ACPI_PTR(dw_dma_acpi_id_table),
@@ -305,3 +307,4 @@ module_exit(dw_exit);
 
 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("Synopsys DesignWare DMA Controller platform driver");
+MODULE_ALIAS("platform:" DRV_NAME);