kconfig.bbclass: Add .scmversion dummy
kconfig.bbclass: Add .scmversion dummy

This removes the "+" appended to the version string. The "+" handling is
inconsistent between different service calls, which leads to different
version string outcome. This is the same fix used in kernel.bbclass.

Signed-off-by: Stefan Müller-Klieser <a3e08e35e4a42be768e7d0e76ae1ba321c2a66dd@phytec.de>

PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec