[POWERPC] Use common 52xx of_platform probe code for EFIKA

Now that the device tree has the good properties, we can
remove all the efika_init code by a single call to common code.

While we're modifying that file, a few whitespaces/alignement/typo
fixes are made (nothing significant).

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Paul Mackerras <paulus@samba.org>