powerpc: Print progress of ibm,client-architecture method

The ibm,client-architecture method will often cause a reconfiguration reboot.
When this happens the last thing we see is:

	Hypertas detected, assuming LPAR !

Which doesn't explain what just happened.  Wrap the ibm,client-architecture
so it's clear what is going on:

	Calling ibm,client-architecture... done

In order to maintain the law of conservation of screen real estate, downgrade
two other messages to debug.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>