IB/qib: Cleanup qib_set_part_key() with direct returns

Perhaps the function is better written without
the empty bail: label and without setting ret
and just using return.

Combining the int/bool conversion of any and the
direct returns makes the resulting code clearer.

Tested-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>