spi: mt65xx: Simplify probe function with devm_spi_alloc_master

Switch to the devm variant of spi_alloc_master() to save some gotos.
This patch is a cleanup that brings no functional changes.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220407114428.167091-2-angelogioacchino.delregno@collabora.com


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