acpi/arm64: remove unnecessary cast

DEFINE_RES_IRQ returns struct resource type, so it is
unnecessary to cast it to struct resource.

Remove the unnecessary cast to fix the following sparse warnings:

drivers/acpi/arm64/gtdt.c:355:19: sparse: warning: cast to non-scalar
drivers/acpi/arm64/gtdt.c:355:19: sparse: warning: cast from non-scalar

No functional changes intended.

Signed-off-by: Min-Hua Chen <minhuadotchen@gmail.com>
Acked-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240917233827.73167-1-minhuadotchen@gmail.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: Min-Hua

drivers/acpi/arm64/gtdt.c

@@ -363,7 +363,7 @@ static int __init gtdt_import_sbsa_gwdt(struct acpi_gtdt_watchdog *wd,
 	}
 
 	irq = map_gt_gsi(wd->timer_interrupt, wd->timer_flags);
-	res[2] = (struct resource)DEFINE_RES_IRQ(irq);
+	res[2] = DEFINE_RES_IRQ(irq);
 	if (irq <= 0) {
 		pr_warn("failed to map the Watchdog interrupt.\n");
 		nr_res--;