MN10300: Don't set the dirty bit in the DTLB entries in the TLB-miss handler

Remove the special handling for the Data TLB entry dirty bit in the TLB-miss
handler.  As the code stands, all that it does is to cause us to take a second
data address exception to set the dirty bit.  Instead, we can just let
pte_mkdirty() set the bit.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>