mfd: dln2: More sanity checking for endpoints

It is not enough to check for the number of endpoints.
The types must also be correct.

Reported-and-tested-by:  <syzbot+48a2851be24583b864dc@syzkaller.appspotmail.com>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>