Add BOARD_NAME variable to environment.

Change-Id: I6e94a9ea5199f69ec5599747ab20d16b7ddf7b8c
diff --git a/project.sh b/project.sh
index 2b7d251..fe8adc5 100644
--- a/project.sh
+++ b/project.sh
@@ -15,5 +15,6 @@
 # limitations under the License.
 
 export PROJECT_NAME=mt8167s_excelsior
+export BOARD_NAME=excelsior
 export PLATFORM=mtk