irqchip/gic-v3-its: Fix potential VPE leak on error

jira LE-1907
cve CVE-2021-47373
Rebuild_History Non-Buildable kernel-4.18.0-553.16.1.el8_10
commit-author Kaige Fu <[email protected]>
commit 280bef5

In its_vpe_irq_domain_alloc, when its_vpe_init() returns an error,
there is an off-by-one in the number of VPEs to be freed.

Fix it by simply passing the number of VPEs allocated, which is the
index of the loop iterating over the VPEs.

Fixes: 7d75bbb ("irqchip/gic-v3-its: Add VPE irq domain allocation/teardown")
	Signed-off-by: Kaige Fu <[email protected]>
[maz: fixed commit message]
	Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/d9e36dee512e63670287ed9eff884a5d8d6d27f2.1631672311.git.kaige.fu@linux.alibaba.com
(cherry picked from commit 280bef5)
	Signed-off-by: Jonathan Maple <[email protected]>

Author: PlaidCat

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

@@ -4502,7 +4502,7 @@ static int its_vpe_irq_domain_alloc(struct irq_domain *domain, unsigned int virq
 
 	if (err) {
 		if (i > 0)
-			its_vpe_irq_domain_free(domain, virq, i - 1);
+			its_vpe_irq_domain_free(domain, virq, i);
 
 		its_lpi_free(bitmap, base, nr_ids);
 		its_free_prop_table(vprop_page);