x86: switch to kernel_clone()

The old _do_fork() helper is removed in favor of the new kernel_clone() helper.
The latter adheres to naming conventions for kernel internal syscall helpers.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Link: https://lore.kernel.org/r/20200819104655.436656-8-christian.brauner@ubuntu.com

arch/x86/kernel/sys_ia32.c

@@ -251,6 +251,6 @@ COMPAT_SYSCALL_DEFINE5(ia32_clone, unsigned long, clone_flags,
 		.tls		= tls_val,
 	};
 
-	return _do_fork(&args);
+	return kernel_clone(&args);
 }
 #endif /* CONFIG_IA32_EMULATION */