wandboard: Remove unneeded return code

There is no need to handle this return code, so just remove it.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

board/wandboard/post-image.sh

@@ -13,5 +13,3 @@ genimage \
   --outputpath "${BINARIES_DIR}" \
   --config "${GENIMAGE_CFG}"
 
-RET=${?}
-exit ${RET}