drivers: macintosh: rack-meter: fix bogus memsets

Fix bogus memsets pointed out by sparse:

linux-v4.3/drivers/macintosh/rack-meter.c:157:15: warning: memset with byte count of 0
linux-v4.3/drivers/macintosh/rack-meter.c:158:15: warning: memset with byte count of 0

Probably "&" is mistyped "*"; use ARRAY_SIZE to make it more safe.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

drivers/macintosh/rack-meter.c

@@ -154,8 +154,8 @@ static void rackmeter_do_pause(struct rackmeter *rm, int pause)
 		DBDMA_DO_STOP(rm->dma_regs);
 		return;
 	}
-	memset(rdma->buf1, 0, SAMPLE_COUNT & sizeof(u32));
-	memset(rdma->buf2, 0, SAMPLE_COUNT & sizeof(u32));
+	memset(rdma->buf1, 0, ARRAY_SIZE(rdma->buf1));
+	memset(rdma->buf2, 0, ARRAY_SIZE(rdma->buf2));
 
 	rm->dma_buf_v->mark = 0;