LibC: Remove duplicate log statement

Now that warnln() also outputs to the debug console, this would print
the error twice.

Userland/Libraries/LibC/stdio.cpp

@@ -1009,7 +1009,6 @@ int snprintf(char* buffer, size_t size, char const* fmt, ...)
 void perror(char const* s)
 {
     int saved_errno = errno;
-    dbgln("perror(): {}: {}", s, strerror(saved_errno));
     warnln("{}: {}", s, strerror(saved_errno));
 }