usb: musb: core: added missing const qualifier to musb_hdrc_platform_data::config

The musb_hdrc_platform_data::config was defined as a non-const pointer.
However some drivers (e.g. the ux500) set up this pointer to point to a
static structure, which is potentially dangerous. Since the musb core
uses the pointer in a read-only manner the const qualifier was added to
protect the content of the config.
Signed-off-by: NPetr Kulhavy <petr@barix.com>
Acked-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NBin Liu <b-liu@ti.com>
Signed-off-by: NFelipe Balbi <balbi@kernel.org>

drivers/usb/musb/musb_core.c

@@ -1901,7 +1901,7 @@ static void musb_recover_from_babble(struct musb *musb)
  */
 
 static struct musb *allocate_instance(struct device *dev,
-		struct musb_hdrc_config *config, void __iomem *mbase)
+		const struct musb_hdrc_config *config, void __iomem *mbase)
 {
 	struct musb		*musb;
 	struct musb_hw_ep	*ep;

drivers/usb/musb/musb_core.h

@@ -438,7 +438,7 @@ struct musb {
 	 */
 	unsigned                double_buffer_not_ok:1;
 
-	struct musb_hdrc_config	*config;
+	const struct musb_hdrc_config *config;
 
 	int			xceiv_old_state;
 #ifdef CONFIG_DEBUG_FS

include/linux/usb/musb.h

@@ -124,7 +124,7 @@ struct musb_hdrc_platform_data {
 	int		(*set_power)(int state);
 
 	/* MUSB configuration-specific details */
-	struct musb_hdrc_config	*config;
+	const struct musb_hdrc_config *config;
 
 	/* Architecture specific board data	*/
 	void		*board_data;