HID: export hid_report_type to uapi

When we are dealing with eBPF, we need to have access to the report type.
Currently our implementation differs from the USB standard, making it
impossible for users to know the exact value besides hardcoding it
themselves.

And instead of a blank define, convert it as an enum.

Note that we need to also do change in the ll_driver API, but given
that this will have a wider impact outside of this tree, we leave this
as a TODO for the future.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20220902132938.2409206-10-benjamin.tissoires@redhat.com

include/uapi/linux/hid.h

@@ -42,6 +42,18 @@
 #define USB_INTERFACE_PROTOCOL_KEYBOARD	1
 #define USB_INTERFACE_PROTOCOL_MOUSE	2
 
+/*
+ * HID report types --- Ouch! HID spec says 1 2 3!
+ */
+
+enum hid_report_type {
+	HID_INPUT_REPORT		= 0,
+	HID_OUTPUT_REPORT		= 1,
+	HID_FEATURE_REPORT		= 2,
+
+	HID_REPORT_TYPES,
+};
+
 /*
  * HID class requests
  */