usb: remove code associated with !CONFIG_PPC_MERGE

Now that arch/ppc is gone we don't need CONFIG_PPC_MERGE anymore remove
the dead code associated with !CONFIG_PPC_MERGE.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>