Simplify match arms

Author: jonas-schievink

src/generate.rs

@@ -243,9 +243,8 @@ pub fn interrupt(
     match *target {
         Target::CortexM => {
             let is_armv6 = match device.cpu {
-                Some(ref cpu) if cpu.name.starts_with("CM0") => true,
-                Some(_) => false,
-                _ => true,  // default to armv6 when the <cpu> section is missing
+                Some(ref cpu) => cpu.name.starts_with("CM0"),
+                None => true,  // default to armv6 when the <cpu> section is missing
             };
 
             if is_armv6 {