drivers: cosmetic: Convert SPDX license tags to Linux Kernel style

Complete in the drivers directory the work started with
commit 83d290c56fab ("SPDX: Convert all of our single
license tags to Linux Kernel style").

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/drivers/usb/dwc3/dwc3-generic.c b/drivers/usb/dwc3/dwc3-generic.c
index ca63eac..56c9fd6 100644
--- a/drivers/usb/dwc3/dwc3-generic.c
+++ b/drivers/usb/dwc3/dwc3-generic.c
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier:     GPL-2.0
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Generic DWC3 Glue layer
  *