iommu/amd: Don't call early_amd_iommu_init() when AMD IOMMU is disabled

Don't even try to initialize the AMD IOMMU hardware when amd_iommu=off has been
passed on the kernel command line.

References: https://bugzilla.kernel.org/show_bug.cgi?id=212133
References: https://bugzilla.suse.com/show_bug.cgi?id=1183132
Cc: stable@vger.kernel.org # v5.11
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20210317091037.31374-3-joro@8bytes.org
Acked-by: Huang Rui <ray.huang@amd.com>

drivers/iommu/amd/init.c

@@ -2919,12 +2919,12 @@ static int __init state_next(void)
 		}
 		break;
 	case IOMMU_IVRS_DETECTED:
-		ret = early_amd_iommu_init();
-		init_state = ret ? IOMMU_INIT_ERROR : IOMMU_ACPI_FINISHED;
-		if (init_state == IOMMU_ACPI_FINISHED && amd_iommu_disabled) {
-			pr_info("AMD IOMMU disabled\n");
+		if (amd_iommu_disabled) {
 			init_state = IOMMU_CMDLINE_DISABLED;
 			ret = -EINVAL;
+		} else {
+			ret = early_amd_iommu_init();
+			init_state = ret ? IOMMU_INIT_ERROR : IOMMU_ACPI_FINISHED;
 		}
 		break;
 	case IOMMU_ACPI_FINISHED: