[MLBEDSW-2657] Softmax uint8/int8

Added graph rewrite of Softmax for uint8/int8.

Signed-off-by: Fredrik Svedberg <fredrik.svedberg@arm.com>
Change-Id: Iecdd5d2cd3156a601b3313debba4a3562e6be5d7
diff --git a/ethosu/vela/architecture_features.py b/ethosu/vela/architecture_features.py
index 2e53a69..5453f2c 100644
--- a/ethosu/vela/architecture_features.py
+++ b/ethosu/vela/architecture_features.py
@@ -94,7 +94,7 @@
     IFM16 = 1
     IFM8_Elementwise = 2
     IFM16_Elementwise = 3
-    IFM32_Elementwise = 4
+    IFM32 = 4
     Acc16 = 5
     Acc32 = 6
     Acc40 = 7