powerpc/82xx: Delete an unnecessary of_node_put() call in pq2ads_pci_init_irq()

A null pointer would be passed to a call of the function “of_node_put”
immediately after a call of the function “of_find_compatible_node” failed
at one place.
Remove this superfluous function call.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/9c060a41-438b-6fb8-d549-37c72fae4898@web.de