Doh. Change the name of the substituted variable

... to match the substituted name.

Fixes #966.

Signed-off-by: Alexey Neyman <stilor@att.net>

ct-ng.in

@@ -229,7 +229,7 @@ source: .config
 	$(SILENT)CT_SOURCE=y $(bash) $(CT_LIB_DIR)/scripts/crosstool-NG.sh
 
 build: .config
-	$(SILENT)BUILD_NCPUS=`@@CT_cpucount@@ 2>/dev/null || echo 0` \
+	$(SILENT)BUILD_NCPUS=`@CPU_COUNT@ 2>/dev/null || echo 0` \
         $(bash) $(CT_LIB_DIR)/scripts/crosstool-NG.sh
 
 build.%: