Revert "[POWERPC] Do firmware feature fixups after features are initialised"

This reverts commit 5a26f6bb.

The original patch causes boot failures when built with ppc64_defconfig.  The
quickest fix is to revert it while alterates are investigated.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>