[POWERPC] Bypass hcall stats until cpu features have run

I noticed that we execute hcalls before cpu feature code has run (eg
for setting up the bolted kernel region).  This means that we may be
executing code that is not appropriate for the processor we have.
Create an unconditional branch that we nop out all the time to fix this.

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