drbd: Return true/false (not 1/0) from bool functions

Return boolean values ("true" or "false") instead of 1 or 0 from bool
functions.  This fixes the following warnings from coccicheck:

./drivers/block/drbd/drbd_req.c:912:9-10: WARNING: return of 0/1 in
function 'remote_due_to_read_balancing' with return type bool

Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Link: https://lore.kernel.org/r/20220406190715.1938174-8-christoph.boehmwalder@linbit.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>