python3-rtimu: don't use trailing slash in S
python3-rtimu: don't use trailing slash in S

* see oe-core base.bbclass changes from:
  https://lists.openembedded.org/g/openembedded-core/message/143159
  https://lists.openembedded.org/g/openembedded-core/message/143161

Signed-off-by: Martin Jansa <516df3ff67e1fa5d153800b15fb204c0a1a389dc@gmail.com>

agherzan/meta-raspberrypi,schnitzeltony/meta-raspberrypi,agherzan/meta-raspberrypi,schnitzeltony/meta-raspberrypi,agherzan/meta-raspberrypi,schnitzeltony/meta-raspberrypi,agherzan/meta-raspberrypi,agherzan/meta-raspberrypi,agherzan/meta-raspberrypi