x86/boot/tboot: Move tboot_force_iommu() to Intel IOMMU

tboot_force_iommu() is only called by the Intel IOMMU driver. Move the
helper into that driver. No functional change intended.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Link: https://lore.kernel.org/r/20220514014322.2927339-7-baolu.lu@linux.intel.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

arch/x86/kernel/tboot.c

@@ -6,7 +6,6 @@
  * Copyright (c) 2006-2009, Intel Corporation
  */
 
-#include <linux/intel-iommu.h>
 #include <linux/init_task.h>
 #include <linux/spinlock.h>
 #include <linux/export.h>
@@ -516,17 +515,3 @@ struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tb
 
 	return dmar_tbl;
 }
-
-int tboot_force_iommu(void)
-{
-	if (!tboot_enabled())
-		return 0;
-
-	if (no_iommu || dmar_disabled)
-		pr_warn("Forcing Intel-IOMMU to enabled\n");
-
-	dmar_disabled = 0;
-	no_iommu = 0;
-
-	return 1;
-}

drivers/iommu/intel/iommu.c

@@ -4019,6 +4019,20 @@ static int __init probe_acpi_namespace_devices(void)
 	return 0;
 }
 
+static __init int tboot_force_iommu(void)
+{
+	if (!tboot_enabled())
+		return 0;
+
+	if (no_iommu || dmar_disabled)
+		pr_warn("Forcing Intel-IOMMU to enabled\n");
+
+	dmar_disabled = 0;
+	no_iommu = 0;
+
+	return 1;
+}
+
 int __init intel_iommu_init(void)
 {
 	int ret = -ENODEV;

include/linux/tboot.h

@@ -126,7 +126,6 @@ extern void tboot_probe(void);
 extern void tboot_shutdown(u32 shutdown_type);
 extern struct acpi_table_header *tboot_get_dmar_table(
 				      struct acpi_table_header *dmar_tbl);
-extern int tboot_force_iommu(void);
 
 #else
 
@@ -136,7 +135,6 @@ extern int tboot_force_iommu(void);
 #define tboot_sleep(sleep_state, pm1a_control, pm1b_control)	\
 					do { } while (0)
 #define tboot_get_dmar_table(dmar_tbl)	(dmar_tbl)
-#define tboot_force_iommu()		0
 
 #endif /* !CONFIG_INTEL_TXT */