ARM: at91: pm: Add of_node_put() before goto

Fix following coccicheck warning:
./arch/arm/mach-at91/pm.c:643:1-33: WARNING: Function
for_each_matching_node_and_match should have of_node_put() before goto

Early exits from for_each_matching_node_and_match should decrement the
node reference counter.

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20211014084555.21422-1-wanjiabing@vivo.com