This patch should *replace* your latest mtd_dataflash patch,
instead of applying on top of things like the preceding patches.
(Sorry.)

It does the spi_driver conversion mentioned in $SUBJECT, and
also includes a couple other updates.  There's a bugfix in
the READ request (don't count the 8 tx bytes with rx), a
performance speedup in ERASE (use block erase, more or less
eight times faster for JFFS2), and more probe() cleanups.

- Dave