irqchip/gic-v3-mbi: Fix uninitialized mbi_lock

mainline inclusion
from mainline-5.0-rc4
commit c530bb8a726a37811e9fb5d68cd6b5408173b545
category: bugfix
bugzilla: 7337
CVE: NA

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

The mbi_lock mutex is left uninitialized, so let's use DEFINE_MUTEX
to initialize it statically.

Fixes: 50528752 ("irqchip/gic-v3: Add support for Message Based Interrupts as an MSI controller")
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NZhang Dianfang <zhangdianfang@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/irqchip/irq-gic-v3-mbi.c

@@ -24,7 +24,7 @@ struct mbi_range {
 	unsigned long		*bm;
 };
 
-static struct mutex		mbi_lock;
+static DEFINE_MUTEX(mbi_lock);
 static phys_addr_t		mbi_phys_base;
 static struct mbi_range		*mbi_ranges;
 static unsigned int		mbi_range_nr;