[FIX]mrp: order view in mrp bom tree view

The order of BOMs is based on the sequence which is
not present in the view. When you open all
BOMs, any order is defined. This patch will display the
list of BOM by product.

opw:681189

addons/mrp/mrp_view.xml

@@ -452,7 +452,7 @@
             <field name="name">mrp.bom.tree</field>
             <field name="model">mrp.bom</field>
             <field name="arch" type="xml">
-                <tree string="Bill of Materials">
+                <tree string="Bill of Materials" default_order="product_tmpl_id">
                     <field name="product_tmpl_id"/>
                     <field name="code"/>
                     <field name="product_id" groups="product.group_product_variant"/>