Remove unneeded dummy function.

Author: reitermarkus

src/libstd/sys/unix/os.rs

@@ -624,12 +624,6 @@ pub fn getpid() -> u32 {
     unsafe { libc::getpid() as u32 }
 }
 
-#[cfg(target_os = "freertos")]
-pub fn getppid() -> u32 {
-    0
-}
-
-#[cfg(not(target_os = "freertos"))]
 pub fn getppid() -> u32 {
     unsafe { libc::getppid() as u32 }
 }