octeontx2-af: Use the correct style for SPDX License Identifier

This patch corrects the SPDX License Identifier style in
header files related to Marvell OcteonTX2 network devices.
It uses an expilict block comment for the SPDX License
Identifier.

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>