conf: local.conf.sample: Fix imx6 rauc wks filename
conf: local.conf.sample: Fix imx6 rauc wks filename

The rauc wks file is called imx6-rauc-sdimage.wks not
imx6-rauc-sdcard.wks. Fix this.

Signed-off-by: Stefan Riedmueller <c3365f3fb46321e09058054bbbd3cb5c9c2c30f7@phytec.de>
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