irqchip/riscv-imsic: Revert "Remove redundant irq_data lookups"

Commit c475c0b71314("irqchip/riscv-imsic: Remove redundant irq_data
lookups") leads to a NULL pointer deference in imsic_msi_update_msg():

virtio_blk virtio1: 8/0/0 default/read/poll queues
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Current kworker/u32:2 pgtable: 4K pagesize, 48-bit VAs, pgdp=0x0000000081c33000
[0000000000000000] pgd=0000000000000000, p4d=0000000000000000
CPU: 5 UID: 0 PID: 75 Comm: kworker/u32:2 Not tainted 6.19.0-rc4-next-20260109 #1 NONE
epc : 0x0
ra : imsic_irq_set_affinity+0x110/0x130

The irq_data argument of imsic_irq_set_affinity() is associated with the
imsic domain and not with the top-level MSI domain. As a consequence the
code dereferences the wrong interrupt chip, which has the
irq_write_msi_msg() callback not populated.

Signed-off-by: Luo Haiyang <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

drivers/irqchip/irq-riscv-imsic-platform.c

···
 		tmp_vec.local_id = new_vec->local_id;
 
 		/* Point device to the temporary vector */
-		imsic_msi_update_msg(d, &tmp_vec);
+		imsic_msi_update_msg(irq_get_irq_data(d->irq), &tmp_vec);
 	}
 
 	/* Point device to the new vector */
-	imsic_msi_update_msg(d, new_vec);
+	imsic_msi_update_msg(irq_get_irq_data(d->irq), new_vec);
 
 	/* Update irq descriptors with the new vector */
 	d->chip_data = new_vec;