adb_kbd.c: Fix function key definitions

Fix typo, where last definition should have been F16 instead of F15.
Found with -Woverride-init

Signed-off-by: Amadeusz Sławiński <amade@asmblr.net>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
1 file changed