aspeed/scu: Fix valid access size on AST2400

The read access size of the SCU registers can be 1/2/4 bytes and write
is 4 bytes and all Aspeed models would need a .valid.accepts() handler.

For the moment, set the min access size to 1 byte to cover both read
and write operations on the AST2400 but keep the min access size of
the other SoCs to 4 bytes as this is an unusual access size.

This fixes support for some old firmware doing 2 bytes reads on the
AST2400 SoC.

Reported-by: Erik Smit <erik.lucas.smit@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Message-Id: <20200819100956.2216690-5-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

hw/misc/aspeed_scu.c

@@ -328,9 +328,10 @@ static const MemoryRegionOps aspeed_ast2400_scu_ops = {
     .read = aspeed_scu_read,
     .write = aspeed_ast2400_scu_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
-    .valid.min_access_size = 4,
-    .valid.max_access_size = 4,
-    .valid.unaligned = false,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 4,
+    },
 };
 
 static const MemoryRegionOps aspeed_ast2500_scu_ops = {