zsmalloc: drop unused member 'mapping_area->huge'

When unmapping a huge class page in zs_unmap_object, the page will be
unmapped by kmap_atomic.  the "!area->huge" branch in __zs_unmap_object
is alway true, and no code set "area->huge" now, so we can drop it.

Signed-off-by: YiPing Xu <xuyiping@huawei.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/zsmalloc.c

@@ -281,7 +281,6 @@ struct mapping_area {
 #endif
 	char *vm_addr; /* address of kmap_atomic()'ed pages */
 	enum zs_mapmode vm_mm; /* mapping mode */
-	bool huge;
 };
 
 static int create_handle_cache(struct zs_pool *pool)
@@ -1127,11 +1126,9 @@ static void __zs_unmap_object(struct mapping_area *area,
 		goto out;
 
 	buf = area->vm_buf;
-	if (!area->huge) {
-		buf = buf + ZS_HANDLE_SIZE;
-		size -= ZS_HANDLE_SIZE;
-		off += ZS_HANDLE_SIZE;
-	}
+	buf = buf + ZS_HANDLE_SIZE;
+	size -= ZS_HANDLE_SIZE;
+	off += ZS_HANDLE_SIZE;
 
 	sizes[0] = PAGE_SIZE - off;
 	sizes[1] = size - sizes[0];