can: sun4i_can: sun4i_can_interrupt(): fix max irq loop handling

Reading the interrupt register `SUN4I_REG_INT_ADDR` causes all of its bits
to be reset. If we ever reach the condition of handling more than
`SUN4I_CAN_MAX_IRQ` IRQs, we will have read the register and reset all its
bits but without actually handling the interrupt inside of the loop body.

This may, among other issues, cause us to never `netif_wake_queue()` again
after a transmission interrupt.

Fixes: 0738eff14d81 ("can: Allwinner A10/A20 CAN Controller support - Kernel module")
Cc: [e-mail]
Co-developed-by: Thomas Mühlbacher <[e-mail]>
Signed-off-by: Thomas Mühlbacher <[e-mail]>
Acked-by: Jernej Skrabec <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Marc Kleine-Budde <[e-mail]>

drivers/net/can/sun4i_can.c

···
 	u8 isrc, status;
 	int n = 0;
 
-	while ((isrc = readl(priv->base + SUN4I_REG_INT_ADDR)) &&
-	       (n < SUN4I_CAN_MAX_IRQ)) {
+	while ((n < SUN4I_CAN_MAX_IRQ) &&
+	       (isrc = readl(priv->base + SUN4I_REG_INT_ADDR))) {
 		n++;
 		status = readl(priv->base + SUN4I_REG_STA_ADDR);