update-linux-headers: Rename SW_MAX to SW_MAX_

update-linux-headers: Rename SW_MAX to SW_MAX_

The next commit will compile hw/input/virtio-input.c and
hw/input/virtio-input-hid.c even when CONFIG_LINUX is off.  These
files include both "include/standard-headers/linux/input.h" and
<windows.h> then.  Doesn't work, because both define SW_MAX.  We don't
actually use it.  Patch input.h to define SW_MAX_ instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1444320700-26260-2-git-send-email-armbru@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>