main: don't limit upper bound of pid when checking pidfile

This commit removes the upper bound check for the PID, letting NetworkManager recognize a PID from the pidfile higher than 2^16.
The PID limit is often set higher than 2^16 (65536) on 64-bit systems, resulting in the pidfile being ignored and subsequently deleted if the currently running instance of NetworkManager has a pid higher than 2^16.

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1727

src/core/main-utils.c

@@ -174,7 +174,7 @@ nm_main_utils_ensure_not_running_pidfile(const char *pidfile)
 
     errno = 0;
     pid   = strtol(contents, NULL, 10);
-    if (pid <= 0 || pid > 65536 || errno)
+    if (pid <= 0 || errno)
         return;
 
     nm_clear_g_free(&contents);