TOSA: Elementwise Rank > 4 and Batch > 1

Added support for elementwise operations:
 -Support for up to Rank == 6
 -Support for Batch > 1 for Rank == 4
 -For binary elementwise ops this includes handling
  of broadcasting in dimensions above H-dimension

Signed-off-by: Patrik Gustavsson <patrik.gustavsson@arm.com>
Change-Id: I73850bbfb288077a99bd2ceecbf989172016da24
diff --git a/ethosu/vela/shape4d.py b/ethosu/vela/shape4d.py
index fd67403..08b2a6a 100644
--- a/ethosu/vela/shape4d.py
+++ b/ethosu/vela/shape4d.py
@@ -136,6 +136,9 @@
     def elements(self):
         return self.batch * self.width * self.height * self.depth
 
+    def dot_prod(self, rhs):
+        return self.batch * rhs.batch + self.width * rhs.width + self.height * rhs.height + self.depth * rhs.depth
+
     def elements_wh(self):
         return self.width * self.height