HID: allow resizing and replacing report descriptors

Update hid_driver's report_fixup prototype to allow changing report
descriptor size and/or returning completely different report descriptor.
Update existing usage accordingly.

This is to give more freedom in descriptor fixup and to allow having a whole
fixed descriptor in the code for the sake of readability.

Signed-off-by: Nikolai Kondrashov <spbnick@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-elecom.c b/drivers/hid/hid-elecom.c
index 7a40878..6e31f30 100644
--- a/drivers/hid/hid-elecom.c
+++ b/drivers/hid/hid-elecom.c
@@ -20,14 +20,15 @@
 
 #include "hid-ids.h"
 
-static void elecom_report_fixup(struct hid_device *hdev, __u8 *rdesc,
-		unsigned int rsize)
+static __u8 *elecom_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
 {
-	if (rsize >= 48 && rdesc[46] == 0x05 && rdesc[47] == 0x0c) {
+	if (*rsize >= 48 && rdesc[46] == 0x05 && rdesc[47] == 0x0c) {
 		dev_info(&hdev->dev, "Fixing up Elecom BM084 "
 				"report descriptor.\n");
 		rdesc[47] = 0x00;
 	}
+    return rdesc;
 }
 
 static const struct hid_device_id elecom_devices[] = {