[POWERPC] Fix MAX_ORDER config problem

[POWERPC] Fix MAX_ORDER config problem

The allyesconfig (among others) build was giving this:

In file included from include/linux/gfp.h:4,
                 from include/linux/slab.h:14,
                 from include/linux/percpu.h:5,
                 from include2/asm/time.h:18,
                 from include2/asm/cputime.h:26,
                 from include/linux/sched.h:67,
                 from
arch/powerpc/kernel/asm-offsets.c:17:
include/linux/mmzone.h:791:2: error: #error Allocator MAX_ORDER exceeds SECTION_SIZE

Kconfig options are order depenendent, so move the setting of
FORCE_MAX_ZONEORDER to after the setting of PPC_64K_PAGES. Also add an
explicit !PPC_64K_PAGES.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>