IB/qib: Fix for broken sparse warning fix

IB/qib: Fix for broken sparse warning fix

commit d359f35430c4ea4dd4e24d809aeaeff1fa54c314 upstream.

Commit 1fb9fed6d489 ("IB/qib: Fix QP RCU sparse warning") broke QP
hash list deletion in qp_remove() badly.

This patch restores the former for loop behavior, while still fixing
the sparse warnings.

Reviewed-by: Gary Leshner <gary.s.leshner@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>