xtensa: 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/20220703141203.147893-15-rppt@kernel.orgSigned-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Helge Deller <deller@gmx.de>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Xuerui Wang <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/xtensa/include/asm/pgalloc.h

@@ -29,7 +29,7 @@
 static inline pgd_t*
 pgd_alloc(struct mm_struct *mm)
 {
-	return (pgd_t*) __get_free_pages(GFP_KERNEL | __GFP_ZERO, PGD_ORDER);
+	return (pgd_t*) __get_free_page(GFP_KERNEL | __GFP_ZERO);
 }
 
 static inline void ptes_clear(pte_t *ptep)

arch/xtensa/include/asm/pgtable.h

@@ -57,7 +57,6 @@
 #define PTRS_PER_PTE		1024
 #define PTRS_PER_PTE_SHIFT	10
 #define PTRS_PER_PGD		1024
-#define PGD_ORDER		0
 #define USER_PTRS_PER_PGD	(TASK_SIZE/PGDIR_SIZE)
 #define FIRST_USER_PGD_NR	(FIRST_USER_ADDRESS >> PGDIR_SHIFT)