powerpc/mm/nohash: Move definition of PGALLOC_GFP to fix build errors

In some obscure Book3E configs (randconfig) we can end up missing a
definition for PGALLOC_GFP in pgtable_64.c.

Fix it by moving the definition to asm/pgalloc.h.

Fixes: de3b8761 ("powerpc/mm/book(e)(3s)/64: Add page table accounting")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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

@@ -41,8 +41,6 @@ extern struct kmem_cache *pgtable_cache[];
 			pgtable_cache[(shift) - 1];	\
 		})
 
-#define PGALLOC_GFP GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO
-
 extern pte_t *pte_fragment_alloc(struct mm_struct *, unsigned long, int);
 extern void pte_fragment_free(unsigned long *, int);
 extern void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift);

arch/powerpc/include/asm/pgalloc.h

@@ -17,6 +17,8 @@ static inline gfp_t pgtable_gfp_flags(struct mm_struct *mm, gfp_t gfp)
 }
 #endif /* MODULE */
 
+#define PGALLOC_GFP (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO)
+
 #ifdef CONFIG_PPC_BOOK3S
 #include <asm/book3s/pgalloc.h>
 #else