hid: Reset kbd modifiers on reset

When resetting the keyboard, we need to reset not just the pending keystrokes,
but also any pending modifiers. Otherwise there's a race when we're getting
reset while running an escape sequence (modifier 0x100).

Cc: qemu-stable@nongnu.org
Signed-off-by: Alexander Graf <agraf@suse.de>
Message-id: 1498117295-162030-1-git-send-email-agraf@suse.de
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit 51dbea77)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>