powerpc/5200: Bring the legacy fsl_spi_platform_data hooks back

In commit 364fdbc0 ("spi_mpc83xx:
rework chip selects handling"), I merged activate_cs and deactivate_cs
hooks into cs_control, but I overlooked that mpc52xx_psc_spi driver
is using these hooks too. And that resulted in the following build
failure:

CC      drivers/spi/mpc52xx_psc_spi.o
drivers/spi/mpc52xx_psc_spi.c: In function 'mpc52xx_psc_spi_do_probe':
drivers/spi/mpc52xx_psc_spi.c:398: error: 'struct fsl_spi_platform_data'
has no member named 'activate_cs'
drivers/spi/mpc52xx_psc_spi.c:399: error: 'struct fsl_spi_platform_data'
has no member named 'deactivate_cs'
make[2]: *** [drivers/spi/mpc52xx_psc_spi.o] Error 1

This patch simply adds the legacy hooks back for 2.6.30, and for
2.6.31 we'll convert the driver to ->cs_control.

Reported-by: Subrata Modak <subrata@linux.vnet.ibm.com>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>