powerpc/nohash: Remove pgd_huge() stub

linux/hugetlb.h has a fallback pgd_huge() macro for when
pgd_huge is not defined.

Remove the powerpc redundant definitions.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ae6aa7fce84f7abcbf67f534271a4a6dd7949b0d.1662543243.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/nohash/pgtable.h

@@ -277,12 +277,6 @@ static inline int pud_huge(pud_t pud)
 	return 0;
 }
 
-static inline int pgd_huge(pgd_t pgd)
-{
-	return 0;
-}
-#define pgd_huge		pgd_huge
-
 #define is_hugepd(hpd)		(hugepd_ok(hpd))
 #endif
 

arch/powerpc/include/asm/page.h

@@ -311,7 +311,6 @@ static inline bool pfn_valid(unsigned long pfn)
 
 #ifndef CONFIG_HUGETLB_PAGE
 #define is_hugepd(pdep)		(0)
-#define pgd_huge(pgd)		(0)
 #endif /* CONFIG_HUGETLB_PAGE */
 
 struct page;