misc: microchip: pci1xxxx: Fix a memory leak in the error handling of gp_aux_bus_probe()

'aux_bus' is freed in the remove function but not in the error handling
path of the probe.

Use devm_kzalloc() to simplify the remove function and fix the leak in the
probe.

Fixes: 393fc2f5 ("misc: microchip: pci1xxxx: load auxiliary bus driver for the PIO function in the multi-function endpoint of pci1xxxx device.")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/17e19926669a1654e5f2495bf3b289581183d02e.1663482259.git.christophe.jaillet@wanadoo.fr


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