uio: uio_dmem_genirq: convert simple allocations to device-managed

This change converts the simple allocations in the driver to used
device-managed allocation functions.
This removes the error path entirely in the probe function, and reduces
some code in the remove function.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201120075625.12272-1-alexandru.ardelean@analog.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>