spi_mpc8xxx: s/83xx/8xxx/g

Since we renamed the file, we might want to rename the file internals too.

Though we don't bother with changing platform driver name and platform
module alias.  The stuff is legacy and hopefully we'll remove it soon.

Suggested-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>