ionic: make spdxcheck.py happy

Headers ionic_if.h and ionic_regs.h are licensed under three alternative
licenses and the used SPDX-License-Identifier expression makes
./scripts/spdxcheck.py complain:

drivers/net/ethernet/pensando/ionic/ionic_if.h: 1:52 Syntax error: OR
drivers/net/ethernet/pensando/ionic/ionic_regs.h: 1:52 Syntax error: OR

As OR is associative, it is irrelevant if the parentheses are put around
the first or the second OR-expression.

Simply add parentheses to make spdxcheck.py happy.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>