ice: fix reservation of resources for RDMA when disabled

If the CONFIG_INFINIBAND_IRDMA symbol is not enabled as a module or a
built-in, then don't let the driver reserve resources for RDMA. The result
of this change is a large savings in resources for older kernels, and a
cleaner driver configuration for the IRDMA=n case for old and new kernels.

Implement this by avoiding enabling the RDMA capability when scanning
hardware capabilities.

Note: Loading the out-of-tree irdma driver in connection to the in-kernel
ice driver, is not supported, and should not be attempted, especially when
disabling IRDMA in the kernel config.

Fixes: d25a0fc4 ("ice: Initialize RDMA support")
Signed-off-by: Jesse Brandeburg <jbrandeburg@cloudflare.com>
Acked-by: Dave Ertman <david.m.ertman@intel.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Tested-by: Rinitha S <sx.rinitha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>