unix/unix_mphal: Adjust #if in mp_hal_stdin_rx_chr to improve format.

ports/unix/unix_mphal.c

@@ -147,7 +147,6 @@ static int call_dupterm_read(size_t idx) {
 #endif
 
 int mp_hal_stdin_rx_chr(void) {
-    unsigned char c;
 #if MICROPY_PY_OS_DUPTERM
     // TODO only support dupterm one slot at the moment
     if (MP_STATE_VM(dupterm_objs[0]) != MP_OBJ_NULL) {
@@ -162,21 +161,20 @@ int mp_hal_stdin_rx_chr(void) {
             c = '\r';
         }
         return c;
-    } else {
-        main_term:;
-#endif
-        MP_THREAD_GIL_EXIT();
-        int ret = read(0, &c, 1);
-        MP_THREAD_GIL_ENTER();
-        if (ret == 0) {
-            c = 4; // EOF, ctrl-D
-        } else if (c == '\n') {
-            c = '\r';
-        }
-        return c;
-#if MICROPY_PY_OS_DUPTERM
     }
+main_term:;
 #endif
+
+    MP_THREAD_GIL_EXIT();
+    unsigned char c;
+    int ret = read(0, &c, 1);
+    MP_THREAD_GIL_ENTER();
+    if (ret == 0) {
+        c = 4; // EOF, ctrl-D
+    } else if (c == '\n') {
+        c = '\r';
+    }
+    return c;
 }
 
 void mp_hal_stdout_tx_strn(const char *str, size_t len) {