xtensa: switch to generic clone()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 0d1f36a..2481f26 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -16,6 +16,7 @@
 	select GENERIC_KERNEL_THREAD
 	select GENERIC_KERNEL_EXECVE
 	select ARCH_WANT_OPTIONAL_GPIOLIB
+	select CLONE_BACKWARDS
 	help
 	  Xtensa processors are 32-bit RISC machines designed by Tensilica
 	  primarily for embedded systems.  These processors are both