Input: allocate keycode for "Selective Screenshot" key

New Chrome OS keyboards have a "snip" key that is basically a selective
screenshot (allows a user to select an area of screen to be copied).
Allocate a keycode for it.
Signed-off-by: Rajat Jain <rajatja@google.com>
Reviewed-by: Harry Cutts <hcutts@chromium.org>
Link: https://lore.kernel.org/r/20200313180333.75011-1-rajatja@google.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

include/uapi/linux/input-event-codes.h

@@ -652,6 +652,9 @@
 /* Electronic privacy screen control */
 #define KEY_PRIVACY_SCREEN_TOGGLE	0x279
 
+/* Select an area of screen to be copied */
+#define KEY_SELECTIVE_SCREENSHOT	0x280
+
 /*
  * Some keyboards have keys which do not have a defined meaning, these keys
  * are intended to be programmed / bound to macros by the user. For most