[POWERPC] mpc5200: normalize compatible property bindings

Update MPC5200 drivers to also look for compatible properties in the
form "fsl,mpc5200-*" to better conform to open firmware generic names
recommended practice as published here:

http://www.openfirmware.org/1275/practice/gnames/gnamv14a.html

This patch should *not* break compatibility with older device trees
which do not use the 'fsl,' prefix.  The drivers will still bind against
the older names also.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>