driver::hid: Allow compiling base::Keyboard without KeyboardioHID

If `HID_BOOT_PROTOCOL` is undefined, define it ourselves (the value is set by
the USB standard, so we can do that). This allows compiling the base class
without KeyboardioHID, letting our HID base driver be completely independent of
it.

Signed-off-by: Gergely Nagy <algernon@keyboard.io>

src/kaleidoscope/driver/hid/base/Keyboard.h

@@ -20,6 +20,10 @@
 
 #include "kaleidoscope/key_defs.h"
 
+#ifndef HID_BOOT_PROTOCOL
+#define HID_BOOT_PROTOCOL 0
+#endif
+
 namespace kaleidoscope {
 namespace driver {
 namespace hid {