This patch slightly change the TLB flush batch mecanism so that we
store the full vaddr (including vsid) when adding an entry to the
batch so that the flush part doesn't have to get to the context.

This cleans it a bit, and paves the way to future updates like
dynamic vsids.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>