powerpc/powermac: Drop unnecessary of_node_put

powerpc/powermac: Drop unnecessary of_node_put

for_each_node_by_name only exits when its first argument is NULL, and a
subsequent call to of_node_put on that argument is unnecessary.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
iterator name for_each_node_by_name;
expression np,E;
identifier l;
@@

for_each_node_by_name(np,...) {
  ... when != break;
      when != goto l;
}
... when != np = E
- of_node_put(np);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Reviewed-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>