powerpc: 8xx: fix a return value error in mpc8xx_pic_init

mpc8xx_pic_init() should return -ENOMEM instead of 0 when
irq_domain_add_linear() return NULL. This cause mpc8xx_pics_init to continue
executing even if mpc8xx_pic_host is NULL.

Fixes: cc76404 ("powerpc/8xx: Fix possible device node reference leak")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220223070223.26845-1-hbh25y@gmail.com

arch/powerpc/platforms/8xx/pic.c

@@ -153,6 +153,7 @@ int __init mpc8xx_pic_init(void)
 	if (mpc8xx_pic_host == NULL) {
 		printk(KERN_ERR "MPC8xx PIC: failed to allocate irq host!\n");
 		ret = -ENOMEM;
+		goto out;
 	}
 
 	ret = 0;