powerpc/mm: Fix build break with RADIX=y & HUGETLBFS=n

If we enable RADIX but disable HUGETLBFS, the build breaks with:

  arch/powerpc/mm/pgtable-radix.c:557:7: error: implicit declaration of function 'pmd_huge'
  arch/powerpc/mm/pgtable-radix.c:588:7: error: implicit declaration of function 'pud_huge'

Fix it by stubbing those functions when HUGETLBFS=n.

Fixes: 4b5d62ca17a1 ("powerpc/mm: add radix__remove_section_mapping()")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/book3s/64/pgtable-4k.h

@@ -47,7 +47,12 @@ static inline int hugepd_ok(hugepd_t hpd)
 	return hash__hugepd_ok(hpd);
 }
 #define is_hugepd(hpd)		(hugepd_ok(hpd))
+
+#else /* !CONFIG_HUGETLB_PAGE */
+static inline int pmd_huge(pmd_t pmd) { return 0; }
+static inline int pud_huge(pud_t pud) { return 0; }
 #endif /* CONFIG_HUGETLB_PAGE */
+
 #endif /* __ASSEMBLY__ */
 
 #endif /*_ASM_POWERPC_BOOK3S_64_PGTABLE_4K_H */

arch/powerpc/include/asm/book3s/64/pgtable-64k.h

@@ -46,6 +46,9 @@ static inline int hugepd_ok(hugepd_t hpd)
 }
 #define is_hugepd(pdep)			0
 
+#else /* !CONFIG_HUGETLB_PAGE */
+static inline int pmd_huge(pmd_t pmd) { return 0; }
+static inline int pud_huge(pud_t pud) { return 0; }
 #endif /* CONFIG_HUGETLB_PAGE */
 
 static inline int remap_4k_pfn(struct vm_area_struct *vma, unsigned long addr,