arm/xen: Fix some refcount leaks

arm/xen: Fix some refcount leaks

The of_find_compatible_node() function returns a node pointer with
refcount incremented, We should use of_node_put() on it when done
Add the missing of_node_put() to release the refcount.

Fixes: 9b08aaa3199a ("ARM: XEN: Move xen_early_init() before efi_init()")
Fixes: b2371587fe0c ("arm/xen: Read extended regions from DT and init Xen resource")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>