spi: atmel-quadspi: Fix use-after-free on unbind

stable inclusion
from stable-5.10.4
commit 9be450fa3f46bcdd5dc077c4d81b1498e182cc2b
bugzilla: 46903

--------------------------------

commit c7b88456 upstream.

atmel_qspi_remove() accesses the driver's private data after calling
spi_unregister_controller() even though that function releases the last
reference on the spi_controller and thereby frees the private data.

Fix by switching over to the new devm_spi_alloc_master() helper which
keeps the private data accessible until the driver has unbound.

Fixes: 2d30ac5e ("mtd: spi-nor: atmel-quadspi: Use spi-mem interface for atmel-quadspi driver")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v5.0+: 5e844cc3: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v5.0+
Cc: Piotr Bugalski <bugalski.piotr@gmail.com>
Link: https://lore.kernel.org/r/4b05c65cf6f1ea3251484fe9a00b4c65478a1ae3.1607286887.git.lukas@wunner.de


Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>