Use product instead of oem for Product specific module

Bug: 64195575
Test: succeeded building product.img with BOARD_PRODUCTIMAGE_PARTITION_SIZE,
BOARD_PRODUCTIMAGE_FILE_SYSTEM_TYPE and PRODUCT_PRODUCT_VERITY_PARTITION.
Change-Id: Icc4f8c16bc389fe20db680849f311d02df1299c3
diff --git a/android/config.go b/android/config.go
index 2ce7f48..b5ec975 100644
--- a/android/config.go
+++ b/android/config.go
@@ -676,11 +676,11 @@
 	return "odm"
 }
 
-func (c *deviceConfig) OemPath() string {
-	if c.config.ProductVariables.OemPath != nil {
-		return *c.config.ProductVariables.OemPath
+func (c *deviceConfig) ProductPath() string {
+	if c.config.ProductVariables.ProductPath != nil {
+		return *c.config.ProductVariables.ProductPath
 	}
-	return "oem"
+	return "product"
 }
 
 func (c *deviceConfig) BtConfigIncludeDir() string {