IB/core: Change filter function return type from int to bool

Filter functions returns either 0 or 1, therefore better change their
return type from int to bool to reflect the same.  Additionally some
filter functions have suffix of _filter some doesn't.  Make all filter
function consistent to have __filter suffix to improve code readability.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>