MLBEDSW-4738 Reinstate find_block_config from v2.1

Reinstated the v2.1.0 functionality for find_block_configs(). This is
used exclusively by the external API.

Signed-off-by: Jacob Bohlin <jacob.bohlin@arm.com>
Change-Id: I6977f13866957edb083769658cc8c57c2b3556fb
diff --git a/ethosu/vela/architecture_allocator.py b/ethosu/vela/architecture_allocator.py
index 3c49eb1..32502e3 100644
--- a/ethosu/vela/architecture_allocator.py
+++ b/ethosu/vela/architecture_allocator.py
@@ -412,4 +412,5 @@
     config.layout = layout
     config.bank_size = arch.shram_bank_size
     config.ifm_block = ifm_block
+    config.ofm_block = block_config
     return config