spi: spi-fsl-dspi: Remove usage of devm_kzalloc

commit 973fbce69ed8e79b5fe3ad19cfecb581a7ef8048 upstream.

devm_* API was supposed to be used only in probe function call.
Memory is allocated at 'probe' and free automatically at 'remove'.
Usage of devm_* functions outside probe sometimes leads to memory leak.
Avoid using devm_kzalloc in dspi_setup_transfer and use kzalloc instead.
Also add the dspi_cleanup function to free the controller data upon
cleanup.

Acked-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>