IB/ipath: Change packet problems vs chip errors handling and reporting

Some types of packet errors are moderately common with longer IB
cables and large clusters, and are not reported with prints by other
IB HCA drivers.  This suppresses those messages unless the new
__IPATH_ERRPKTDBG bit is set in ipath_debug.  Reporting of temporarily
disabled frequent error interrupts was also made clearer

We also distinguish between chip errors, and bad packets sent or
received in the wording of the messages.

Signed-off-by: Dave Olson <dave.olson@qlogic.com>
Signed-off-by: Bryan O'Sullivan <bryan.osullivan@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>