configs/raspberrypi*: bump kernel version to 64d0a98

configs/raspberrypi*: bump kernel version to 64d0a98

Now based on 4.19.97 (from 4.19.75).

Go back to sha1 version scheme instead of official tag (after
only two tag versions) to get an up-to-date kernel version
(as the offical last tag is for 4.19.94).

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>