usb: gadget: aspeed: fixup vhub port irq handling

This is a follow-on patch for commit a23be4ed ("usb: gadget: aspeed:
improve vhub port irq handling"): for_each_set_bit() is replaced with
simple for() loop because for() loop runs faster on ASPEED BMC.
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/gadget/udc/aspeed-vhub/core.c

@@ -135,13 +135,9 @@ static irqreturn_t ast_vhub_irq(int irq, void *data)
 
 	/* Handle device interrupts */
 	if (istat & vhub->port_irq_mask) {
-		unsigned long bitmap = istat;
-		int offset = VHUB_IRQ_DEV1_BIT;
-		int size = VHUB_IRQ_DEV1_BIT + vhub->max_ports;
-
-		for_each_set_bit_from(offset, &bitmap, size) {
-			i = offset - VHUB_IRQ_DEV1_BIT;
-			ast_vhub_dev_irq(&vhub->ports[i].dev);
+		for (i = 0; i < vhub->max_ports; i++) {
+			if (istat & VHUB_DEV_IRQ(i))
+				ast_vhub_dev_irq(&vhub->ports[i].dev);
 		}
 	}
 

drivers/usb/gadget/udc/aspeed-vhub/vhub.h

@@ -67,6 +67,9 @@
 #define VHUB_IRQ_HUB_EP0_SETUP			(1 << 0)
 #define VHUB_IRQ_ACK_ALL			0x1ff
 
+/* Downstream device IRQ mask. */
+#define VHUB_DEV_IRQ(n)				(VHUB_IRQ_DEVICE1 << (n))
+
 /* SW reset reg */
 #define VHUB_SW_RESET_EP_POOL			(1 << 9)
 #define VHUB_SW_RESET_DMA_CONTROLLER		(1 << 8)