Kernel: Report correct architecture for uname()

Author: https://github.com/gunnarbeutner
Commit: https://github.com/SerenityOS/serenity/commit/a5b4b95a763
Pull-request: https://github.com/SerenityOS/serenity/pull/8317

Kernel/Syscalls/uname.cpp

@@ -23,7 +23,12 @@ KResultOr<FlatPtr> Process::sys$uname(Userspace<utsname*> user_buf)
     memcpy(buf.sysname, "SerenityOS", 11);
     memcpy(buf.release, "1.0-dev", 8);
     memcpy(buf.version, "FIXME", 6);
+#if ARCH(I386)
     memcpy(buf.machine, "i686", 5);
+#else
+    memcpy(buf.machine, "x86_64", 7);
+#endif
+
     memcpy(buf.nodename, g_hostname->characters(), g_hostname->length() + 1);
 
     if (!copy_to_user(user_buf, &buf))