Documentation: hid: fix path to input bus definitions

The UAPI header split failed to update the documentation here; fix things
accordingly.
Signed-off-by: NMartin Kepplinger <martink@posteo.de>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Documentation/hid/hidraw.txt

@@ -81,7 +81,7 @@ of:
 	BUS_HIL
 	BUS_BLUETOOTH
 	BUS_VIRTUAL
-which are defined in linux/input.h.
+which are defined in uapi/linux/input.h.
 
 HIDIOCGRAWNAME(len): Get Raw Name
 This ioctl returns a string containing the vendor and product strings of