ssi: Fix bad printf format specifiers

We should use printf format specifier "%u" instead of "%d" for
argument of type "unsigned int".

Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Alex Chen <alex.chen@huawei.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 5FA280F5.8060902@huawei.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/hw/ssi/xilinx_spi.c b/hw/ssi/xilinx_spi.c
index fec8817..49ff275 100644
--- a/hw/ssi/xilinx_spi.c
+++ b/hw/ssi/xilinx_spi.c
@@ -142,7 +142,7 @@
        irq chain unless things really changed.  */
     if (pending != s->irqline) {
         s->irqline = pending;
-        DB_PRINT("irq_change of state %d ISR:%x IER:%X\n",
+        DB_PRINT("irq_change of state %u ISR:%x IER:%X\n",
                     pending, s->regs[R_IPISR], s->regs[R_IPIER]);
         qemu_set_irq(s->irq, pending);
     }