zram: use IS_ERR_VALUE() to check for zs_malloc() errors

Avoid typecasts that are needed for IS_ERR() and use IS_ERR_VALUE()
instead.

Link: https://lkml.kernel.org/r/[e-mail]
Suggested-by: Andrew Morton <[e-mail]>
Signed-off-by: Sergey Senozhatsky <[e-mail]>
Acked-by: Minchan Kim <[e-mail]>
Cc: Alexey Romanov <[e-mail]>
Cc: Nhat Pham <[e-mail]>
Cc: Nitin Gupta <[e-mail]>
Cc: Suleiman Souhlal <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

drivers/block/zram/zram_drv.c

···
 	 * if we have a 'non-null' handle here then we are coming
 	 * from the slow path and handle has already been allocated.
 	 */
-	if (IS_ERR((void *)handle))
+	if (IS_ERR_VALUE(handle))
 		handle = zs_malloc(zram->mem_pool, comp_len,
 				__GFP_KSWAPD_RECLAIM |
 				__GFP_NOWARN |
 				__GFP_HIGHMEM |
 				__GFP_MOVABLE);
-	if (IS_ERR((void *)handle)) {
+	if (IS_ERR_VALUE(handle)) {
 		zcomp_stream_put(zram->comps[ZRAM_PRIMARY_COMP]);
 		atomic64_inc(&zram->stats.writestall);
 		handle = zs_malloc(zram->mem_pool, comp_len,
 				GFP_NOIO | __GFP_HIGHMEM |
 				__GFP_MOVABLE);
-		if (IS_ERR((void *)handle))
+		if (IS_ERR_VALUE(handle))
 			return PTR_ERR((void *)handle);
 
 		if (comp_len != PAGE_SIZE)