core/ethereum: fix typo in wanchain detection

Reason it worked before: this function would fail to find a network
for wanchain, but the `network` value is only used to determine if
RSKIP60 should be used. That is almost never the case, so missing
network info did not cause an issue.

core/src/apps/ethereum/networks.py

@@ -30,7 +30,7 @@ def by_chain_id(chain_id: int) -> Optional["NetworkInfo"]:
 def by_slip44(slip44: int) -> Optional["NetworkInfo"]:
     if slip44 == SLIP44_WANCHAIN:
         # Coerce to Ethereum
-        slip44 == SLIP44_ETHEREUM
+        slip44 = SLIP44_ETHEREUM
     for n in NETWORKS:
         if n.slip44 == slip44:
             return n