csky: drop definition of PGD_ORDER

This is the order of the page table allocation, not the order of a PGD. 
Since its always hardwired to 0, simply drop it.

Link: https://lkml.kernel.org/r/20220703141203.147893-3-rppt@kernel.orgSigned-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Xuerui Wang <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/csky/include/asm/pgalloc.h

@@ -44,7 +44,7 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 	pgd_t *ret;
 	pgd_t *init;
 
-	ret = (pgd_t *) __get_free_pages(GFP_KERNEL, PGD_ORDER);
+	ret = (pgd_t *) __get_free_page(GFP_KERNEL);
 	if (ret) {
 		init = pgd_offset(&init_mm, 0UL);
 		pgd_init((unsigned long *)ret);

arch/csky/include/asm/pgtable.h

@@ -18,9 +18,8 @@
 /*
  * C-SKY is two-level paging structure:
  */
-#define PGD_ORDER	0
 
-#define PTRS_PER_PGD	((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))
+#define PTRS_PER_PGD	(PAGE_SIZE / sizeof(pgd_t))
 #define PTRS_PER_PMD	1
 #define PTRS_PER_PTE	(PAGE_SIZE / sizeof(pte_t))