Remove socklen_t from platforms where it's no longer used

Author: faern

library/std/src/sys/sgx/net.rs

@@ -538,6 +538,4 @@ pub mod netc {
 
     #[derive(Copy, Clone)]
     pub struct sockaddr {}
-
-    pub type socklen_t = usize;
 }

library/std/src/sys/unsupported/net.rs

@@ -363,6 +363,4 @@ pub mod netc {
 
     #[derive(Copy, Clone)]
     pub struct sockaddr {}
-
-    pub type socklen_t = usize;
 }

library/std/src/sys/wasi/net.rs

@@ -524,6 +524,4 @@ pub mod netc {
 
     #[derive(Copy, Clone)]
     pub struct sockaddr {}
-
-    pub type socklen_t = usize;
 }