memory: atmel-ebi: add missing of_node_put for loop iteration

memory: atmel-ebi: add missing of_node_put for loop iteration

Early exits from for_each_available_child_of_node() should decrement the
node reference counter.  Reported by Coccinelle:

  drivers/memory/atmel-ebi.c:593:1-33: WARNING:
    Function "for_each_available_child_of_node" should have of_node_put() before return around line 604.

Fixes: 6a4ec4cd0888 ("memory: add Atmel EBI (External Bus Interface) driver")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20210423101815.119341-2-krzysztof.kozlowski@canonical.com