[PATCH] powerpc: Fix boot on eMac

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Prevent calling of some platform functions on the clock chips of the eMac
as it seems to cause it to lockup at boot.  For now, add a quirk to prevent
that from happening.  Later, I might find out what's wrong and fix it but
that doesn't seem to be important as the machine appear to work fine
without running those.  It's possible that Darwin doesn't run them.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Nathan Pilatzke <nathanpilatzke@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>