build.rs: fix warning: unexpected cfg condition value: overwrite

warning: unexpected `cfg` condition value: `overwrite`
  --> build.rs:61:15
   |
61 |     #[cfg(not(feature = "overwrite"))]
   |               ^^^^^^^^^^^^^^^^^^^^^
   |
   = note: expected values for `feature` are: `fat_complete`
   = help: consider adding `overwrite` as a feature in `Cargo.toml`
   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
   = note: `#[warn(unexpected_cfgs)]` on by default

warning: unexpected `cfg` condition value: `overwrite`
  --> build.rs:64:11
   |
64 |     #[cfg(feature = "overwrite")]
   |           ^^^^^^^^^^^^^^^^^^^^^

Signed-off-by: Ming Lei <tom.leiming@gmail.com>

build.rs

@@ -58,12 +58,7 @@ MARK_FIX_753(UBLK_U_CMD_DEL_DEV_ASYNC);
 const int Fix753_UBLK_IO_RES_ABORT = UBLK_IO_RES_ABORT;
     "#;
 
-    #[cfg(not(feature = "overwrite"))]
     let outdir = PathBuf::from(env::var("OUT_DIR").unwrap());
-
-    #[cfg(feature = "overwrite")]
-    let outdir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap()).join("src/sys");
-
     let mut builder = bindgen::Builder::default();
     builder = builder.header_contents("include-file.h", INCLUDE);