ppc/xive2: Fix logical / bitwise comparison typo
The comparison as written is always false (perhaps confusingly, because
the functions/macros are not really booleans but return 0 or the tested
bit value). Change to use logical-and.
Resolves: Coverity CID 1593721
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>