irqchip/riscv-imsic: Don't dereference before NULL pointer check

smatch warns about a dereference before check:
drivers/irqchip/irq-riscv-imsic-platform.c:317 imsic_irqdomain_init() warn: variable dereferenced before check 'imsic' (see line 311)    

Cure it by moving the firmware not assignement after the checks.

Fixes: 5942290 ("irqchip/riscv-imsic: Convert to msi_create_parent_irq_domain() helper")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Closes: https://lore.kernel.org/r/202507311953.NFVZkr0a-lkp@intel.com/                                                                                                                                                                                                                                                       ---
 drivers/irqchip/irq-riscv-imsic-platform.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Author: KAGA-KOKO

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

@@ -308,7 +308,6 @@ static const struct msi_parent_ops imsic_msi_parent_ops = {
 int imsic_irqdomain_init(void)
 {
 	struct irq_domain_info info = {
-		.fwnode		= imsic->fwnode,
 		.ops		= &imsic_base_domain_ops,
 		.host_data	= imsic,
 	};
@@ -325,6 +324,7 @@ int imsic_irqdomain_init(void)
 	}
 
 	/* Create Base IRQ domain */
+	info.fwnode = imsic->fwnode,
 	imsic->base_domain = msi_create_parent_irq_domain(&info, &imsic_msi_parent_ops);
 	if (!imsic->base_domain) {
 		pr_err("%pfwP: failed to create IMSIC base domain\n", imsic->fwnode);