Added make files for variable Nougat MR1

Nougat MR1 has different API LEVEL from previous releases,
PRODUCT_SHIPPING_API_LEVEL should be set to 25.

Change-Id: Ib3679bba4105dc99b96224c5f5554c1f0e4ab127
diff --git a/target/product/product_launched_with_n_mr1.mk b/target/product/product_launched_with_n_mr1.mk
new file mode 100644
index 0000000..65d4d3f
--- /dev/null
+++ b/target/product/product_launched_with_n_mr1.mk
@@ -0,0 +1,2 @@
+#PRODUCT_SHIPPING_API_LEVEL indicates the first api level, device has been commercially launced on.
+PRODUCT_SHIPPING_API_LEVEL := 25