[POWERPC] Fix swapper_pg_dir size when CONFIG_PTE_64BIT=y on FSL_BOOKE

The size of swapper_pg_dir is 8k instead of 4k when using 64-bit PTEs
(CONFIG_PTE_64BIT).

This was reported by Cedric Hombourger <chombourger@gmail.com>

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/kernel/asm-offsets.c

@@ -326,8 +326,7 @@ int main(void)
 	DEFINE(VMALLOC_START_VSID, KERNEL_VSID(VMALLOC_START));
 #endif
 
-#ifdef CONFIG_PPC64
 	DEFINE(PGD_TABLE_SIZE, PGD_TABLE_SIZE);
-#endif
+
 	return 0;
 }