Replace proprietary licenes with Apache 2.0 or other compatible license, if possible

[jafingerhut]

$ git clone https://github.com/p4lang/p4-dpdk-target

# cd p4-dpdk-target

$ git log -n 1 | head -n 3
commit 754c69683164465fed03c33ab0592cd75b8875b9
Author: b3n-l <[email protected]>
Date:   Fri Jun 28 18:27:17 2024 +0000

$ find . \! -type d | xargs grep -i confidential | head -n 5
./include/tdi_rt/tdi_rt_attributes.hpp: *  INTEL CONFIDENTIAL
./include/tdi_rt/c_frontend/tdi_rt_attributes.h: *  INTEL CONFIDENTIAL
./include/tdi_rt/c_frontend/tdi_rt_init.h: * BAREFOOT NETWORKS CONFIDENTIAL & PROPRIETARY
./include/tdi_rt/tdi_rt_init.hpp: * BAREFOOT NETWORKS CONFIDENTIAL & PROPRIETARY
./src/tdi_rt/tdi_common/tdi_context_info.hpp: * BAREFOOT NETWORKS CONFIDENTIAL & PROPRIETARY

$ find . \! -type d | xargs grep -i proprietary | head -n 5
./include/tdi_rt/c_frontend/tdi_rt_init.h: * BAREFOOT NETWORKS CONFIDENTIAL & PROPRIETARY
./include/tdi_rt/c_frontend/tdi_rt_init.h: * technical concepts contained herein are proprietary to Barefoot Networks,
./include/tdi_rt/tdi_rt_init.hpp: * BAREFOOT NETWORKS CONFIDENTIAL & PROPRIETARY
./include/tdi_rt/tdi_rt_init.hpp: * technical concepts contained herein are proprietary to Barefoot Networks,
./src/tdi_rt/tdi_common/tdi_context_info.hpp: * BAREFOOT NETWORKS CONFIDENTIAL & PROPRIETARY

For these files, and ideally all source files in this repository that are released under and Apache 2.0 license, please add a comment line near the beginning of the file with exactly this text in it (plus any characters required to make it a comment):

SPDX-License-Identifier: Apache-2.0

[jafingerhut]

@riyazahm22 Pinging you since you made at least one of the commits that added files with "CONFIDENTIAL" and/or "PROPRIETARY" in it.

@swaroopsarma @weiqiand Pinging you since you made many other commits to this repository, and hopefully know the answer, or can find out, about re-licensing these source files.