RDMA/irdma: Use correct kconfig symbol for AUXILIARY_BUS

In Kconfig, references to config symbols do not use the prefix "CONFIG_".

Commit fa0cf568 ("RDMA/irdma: Add irdma Kconfig/Makefile and remove
i40iw") selects config CONFIG_AUXILIARY_BUS in config INFINIBAND_IRDMA,
but intended to select config AUXILIARY_BUS.

Fixes: fa0cf568

 ("RDMA/irdma: Add irdma Kconfig/Makefile and remove i40iw")
Link: https://lore.kernel.org/r/20210817084158.10095-1-lukas.bulwahn@gmail.com
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>