arm64: nmi: fix using wrong shift to set priority

hulk inclusion
category: bugfix
bugzilla: NA
CVE: NA

-------------------------------------------------

We used wrong shift to set the priority of NMI.

Fixes: dec86aedbc8b("arm64: Add support for on-demand backtrace of other CPUs")
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

arch/arm64/kernel/smp.c

@@ -1087,7 +1087,7 @@ void ipi_set_nmi_prio(void __iomem *base, u8 prio)
 	/* clean old priority */
 	prios &= ~(0xff << shift);
 	/* set new priority*/
-	prios |= (prio << offset);
+	prios |= (prio << shift);
 
 	writel_relaxed(prios, base + GICR_IPRIORITYR0 + offset);
 }