Add support for Intel Stratix 10 platform.

Intel Stratix 10 SoC includes a quad-core arm64 cluster and FPGA fabric.

This adds support for reconfiguring FPGA.

Accessing FPGA core of this SoC require the level of privilege EL3,
while kernel runs in EL1 (lower) level of privilege.

This provides an Intel service layer interface that uses SMCCC to pass
queries to the secure-monitor (EL3).

Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D21454