coldfire-qspi: Add support for the Coldfire 5251/5253.

The Coldfire 5251/5253 have a QSPI controller.  Enable selection of the
coldfire-qspi driver if the M525x is selected.

Signed-off-by: Steven King <sfking@fdwdc.com>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>