x86/irq: parenthesize negative constants

x86/irq: parenthesize negative constants

These constants are parenthesized to avoid them from
possibly influencing the semantics of the constructs where it is used,
especially inside macros invocations.

This also resolves some violations of MISRA C Rule 20.7
("Expressions resulting from the expansion of macro parameters shall
be enclosed in parentheses").

No functional change.

Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Acked-by: Jan Beulich <jbeulich@suse.com>