CONFIG_INFINIBAND_HFI1 is not available for thedefaultarchitecture x86.
Result is shown for architecture 64BIT

Intel OPA Gen1 support

modulename: hfi1.ko

configname: CONFIG_INFINIBAND_HFI1

Linux Kernel Configuration
└─>Device Drivers
└─>Staging drivers
└─>RDMA staging drivers
└─>Intel OPA Gen1 support
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This is a low-level driver for Intel OPA Gen1 adapter.

source code: