arm64: kernel: remove non-legit DT warnings when booting using ACPI

Since both CONFIG_ACPI and CONFIG_OF are enabled when booting using ACPI
tables on ARM64 platforms, we get few device tree warnings which are not
valid for ACPI boot. We can use of_have_populated_dt to check if the
device tree is populated or not before throwing out those errors.

This patch uses of_have_populated_dt to remove non legitimate device
tree warning when booting using ACPI tables.

Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/kernel/setup.c

@@ -423,8 +423,13 @@ void __init setup_arch(char **cmdline_p)
 
 static int __init arm64_device_init(void)
 {
-	of_iommu_init();
-	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
+	if (of_have_populated_dt()) {
+		of_iommu_init();
+		of_platform_populate(NULL, of_default_bus_match_table,
+				     NULL, NULL);
+	} else if (acpi_disabled) {
+		pr_crit("Device tree not populated\n");
+	}
 	return 0;
 }
 arch_initcall_sync(arm64_device_init);

arch/arm64/kernel/topology.c

@@ -300,6 +300,6 @@ void __init init_cpu_topology(void)
 	 * Discard anything that was parsed if we hit an error so we
 	 * don't use partial information.
 	 */
-	if (parse_dt_topology())
+	if (of_have_populated_dt() && parse_dt_topology())
 		reset_cpu_topology();
 }