it: silence dead_code warnings for test-only code

src/theme.rs

@@ -43,6 +43,7 @@ impl Color {
         }
     }
 
+    #[cfg_attr(not(feature = "it"), allow(dead_code))]
     pub fn to_rgba_premultiplied(self) -> [u8; 4] {
         [to_u8(self.r), to_u8(self.g), to_u8(self.b), to_u8(self.a)]
     }

src/video/drm.rs

@@ -135,6 +135,7 @@ pub struct Drm {
 }
 
 impl Drm {
+    #[cfg_attr(not(feature = "it"), allow(dead_code))]
     pub fn open_existing(fd: OwnedFd) -> Self {
         Self { fd: Rc::new(fd) }
     }