spi: xilinx: Switch to use devm_spi_alloc_master()

Switch to use devm_spi_alloc_master() to simpify error path.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/20220920114615.2681751-1-yangyingliang@huawei.com


Signed-off-by: Mark Brown <broonie@kernel.org>