powerpc: mpc5200: fix build error on mpc52xx_psc_spi device driver

Commit id 94f38948 (Separate MPC52xx PSC FIOF
regsiters from the rest of PSC) split the PSC fifo registers away from the
core PSC regs.  Doing so broke the mpc52xx_psc_spi driver.

This patch teaches the mpc52xx_psc_spi driver about the new PSC fifo
register definitions.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: David Brownell <david-b@pacbell.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>