parisc: Purge TLB entries after updating page table entry and set page accessed flag in TLB handler

This patch may resolve some races in TLB handling.  Hopefully, TLB
inserts are accesses and protected by spin lock.

If not, we may need to IPI calls and do local purges on PA 2.0.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>