ir: Remove redundant parenthesis.

Author: emilio

src/ir/comp.rs

@@ -356,7 +356,7 @@ impl Bitfield {
             if self.width() as u64 == mem::size_of::<u64>() as u64 * 8 {
                 u64::MAX
             } else {
-                ((1u64 << self.width()) - 1u64)
+                (1u64 << self.width()) - 1u64
             };
 
         unoffseted_mask << self.offset_into_unit()