IB/ipath: Remove bogus RD_ATOMIC checks from modify_qp

The changeset 3859e39d ("IB/ipath: Support larger IB_QP_MAX_DEST_RD_ATOMIC
and IB_QP_MAX_QP_RD_ATOMIC") added support for larger RD_ATOMIC values,
but it failed to take out the stricter checks that were before these and
hence had no effect.  This patch takes out the bogus checks....

Signed-off-by: Arthur Jones <arthur.jones@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>