powerpc/64s: Only set HAVE_ARCH_UNMAPPED_AREA when CONFIG_PPC_64S_HASH_MMU is set

When CONFIG_PPC_64S_HASH_MMU is not set, slice.c is not built and
arch_get_unmapped_area() and arch_get_unmapped_area_topdown() are
not provided because RADIX uses the generic ones.

Therefore, neither set HAVE_ARCH_UNMAPPED_AREA nor
HAVE_ARCH_UNMAPPED_AREA_TOPDOWN.

Fixes: ab57bd7 ("powerpc/mm: Move get_unmapped_area functions to slice.c")
Reported-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/e438c6cc09f94085e56733ed2d6e84333c35292a.1653370913.git.christophe.leroy@csgroup.eu

Author: chleroy

arch/powerpc/include/asm/book3s/64/slice.h

@@ -4,11 +4,13 @@
 
 #ifndef __ASSEMBLY__
 
+#ifdef CONFIG_PPC_64S_HASH_MMU
 #ifdef CONFIG_HUGETLB_PAGE
 #define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 #endif
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
+#endif
 
 #define SLICE_LOW_SHIFT		28
 #define SLICE_LOW_TOP		(0x100000000ul)