Add an option to set the address size per block

When generating iface based register code the register address and size
may actually be different. In the case of the WM8960 that I initially
created this for the address size is 7bits, the register size is 9bits.

Author: SpinFast

src/ir.rs

@@ -73,6 +73,7 @@ pub struct Block {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub description: Option<String>,
     pub items: Vec<BlockItem>,
+    pub address_size: Option<u32>
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]

src/svd2ir.rs

@@ -165,6 +165,7 @@ pub fn convert_peripheral(ir: &mut IR, p: &svd::Peripheral) -> anyhow::Result<()
     // Convert blocks
     for proto in &blocks {
         let mut block = Block {
+            address_size: None,
             extends: None,
             description: proto.description.clone(),
             items: Vec::new(),

src/transform/make_block.rs

@@ -42,6 +42,7 @@ impl MakeBlock {
                 let byte_offset = items[0].byte_offset;
 
                 let b2 = Block {
+                    address_size: None,
                     extends: None,
                     description: None,
                     items: items