The EHINV bit in EntryHi allows a TLB entry to be properly marked
invalid so that EntryHi doesn't have to be set to a unique value to
avoid machine check exceptions due to multiple matching entries.
Unfortunately dump_tlb() doesn't take this into account so it will print
all the uninteresting invalid TLB entries if the current ASID happens to
be 00. Therefore add a condition to skip entries which are marked
invalid with the EHINV bit.