This avoids needing to do a kmalloc > PAGE_SIZE for the main
indirect buffer chunk, it adds an accessor for all reads from
the chunk and caches a single page at a time for subsequent
reads.

changes since v1:
Use a two page pool which should be the most common case
a single packet spanning > PAGE_SIZE will be hit, but I'm
having trouble seeing anywhere we currently generate anything like that.
hopefully proper short page copying at end
added parser_error flag to set deep errors instead of having to test
every ib value fetch.
fixed bug in patch that went to list.
Signed-off-by: NDave Airlie <airlied@redhat.com>

This adds the command stream checker for the RN50, R100 and R200 cards.

It stops any access to 3D registers on RN50, and does checks
on buffer sizes on the r100/r200 cards. It also fixes some texture
sizing checks on r300.
Signed-off-by: NDave Airlie <airlied@redhat.com>