ipmi: Fix macro issues

ipmi: Fix macro issues

Macro parameters should almost always have () around them when used.
llvm reported an error on this.

Remove redundant parenthesis and put parenthesis around the entire
macros with assignments in case they are used in an expression.

Remove some unused macros.

Reported in https://bugs.launchpad.net/bugs/1651167

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1490894892-8055-1-git-send-email-minyard@acm.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>