MLCE-159 Add QAsymmS8 to ArmnnQuantizer

 * Allow per layer quantization from Fp32 to Int8 (QAsymmS8) like TfLite

Signed-off-by: Francis Murtagh <francis.murtagh@arm.com>
Change-Id: I5bbf770aa29d81af3568c15b47d2b2c18e55bb28
diff --git a/src/armnnSerializer/ArmnnSchema.fbs b/src/armnnSerializer/ArmnnSchema.fbs
index d7565a5..ca3db5d 100644
--- a/src/armnnSerializer/ArmnnSchema.fbs
+++ b/src/armnnSerializer/ArmnnSchema.fbs
@@ -37,7 +37,8 @@
     Boolean = 4,
     QuantisedSymm16 = 5, // deprecated
     QAsymmU8 = 6,
-    QSymmS16 = 7
+    QSymmS16 = 7,
+    QAsymmS8 = 8
 }
 
 enum DataLayout : byte {