spi: cadence: Add of_node_put() before return

commit 54b64fb827a0b7afa5cefb7748f880ac6f577fbe from
git@git.assembla.com:cavium/WindRiver.linux.git

Fix following coccicheck warning:
./drivers/spi/spi-cadence-xspi.c:490:1-23: WARNING: Function
for_each_child_of_node should have of_node_put() before return

Early exits from for_each_child_of_node should decrement the
node reference counter.

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Link: https://lore.kernel.org/r/20211015033919.5915-1-wanjiabing@vivo.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Witold Sadowski <wsadowski@marvell.com>
Change-Id: Ib176669fcc5c9793b49f5b31a9e8f2c07f83ca21
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/67405
Reviewed-by: Chandrakala Chavva <cchavva@marvell.com>
Tested-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>