iommu/vt-d: Remove extern from function prototypes

The kernel coding style does not require 'extern' in function prototypes
in .h files, so remove them from drivers/iommu/intel/iommu.h as they are
not needed.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20230331045452.500265-1-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel/iommu.h

@@ -796,18 +796,18 @@ static inline bool context_present(struct context_entry *context)
 	return (context->lo & 1);
 }
 
-extern struct dmar_drhd_unit * dmar_find_matched_drhd_unit(struct pci_dev *dev);
-
-extern int dmar_enable_qi(struct intel_iommu *iommu);
-extern void dmar_disable_qi(struct intel_iommu *iommu);
-extern int dmar_reenable_qi(struct intel_iommu *iommu);
-extern void qi_global_iec(struct intel_iommu *iommu);
-
-extern void qi_flush_context(struct intel_iommu *iommu, u16 did, u16 sid,
-			     u8 fm, u64 type);
-extern void qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
-			  unsigned int size_order, u64 type);
-extern void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
+struct dmar_drhd_unit *dmar_find_matched_drhd_unit(struct pci_dev *dev);
+
+int dmar_enable_qi(struct intel_iommu *iommu);
+void dmar_disable_qi(struct intel_iommu *iommu);
+int dmar_reenable_qi(struct intel_iommu *iommu);
+void qi_global_iec(struct intel_iommu *iommu);
+
+void qi_flush_context(struct intel_iommu *iommu, u16 did,
+		      u16 sid, u8 fm, u64 type);
+void qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
+		    unsigned int size_order, u64 type);
+void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
 			u16 qdep, u64 addr, unsigned mask);
 
 void qi_flush_piotlb(struct intel_iommu *iommu, u16 did, u32 pasid, u64 addr,
@@ -830,17 +830,17 @@ int qi_submit_sync(struct intel_iommu *iommu, struct qi_desc *desc,
  */
 #define QI_OPT_WAIT_DRAIN		BIT(0)
 
-extern int dmar_ir_support(void);
+int dmar_ir_support(void);
 
 void *alloc_pgtable_page(int node, gfp_t gfp);
 void free_pgtable_page(void *vaddr);
 void iommu_flush_write_buffer(struct intel_iommu *iommu);
 struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn);
 
 #ifdef CONFIG_INTEL_IOMMU_SVM
-extern void intel_svm_check(struct intel_iommu *iommu);
-extern int intel_svm_enable_prq(struct intel_iommu *iommu);
-extern int intel_svm_finish_prq(struct intel_iommu *iommu);
+void intel_svm_check(struct intel_iommu *iommu);
+int intel_svm_enable_prq(struct intel_iommu *iommu);
+int intel_svm_finish_prq(struct intel_iommu *iommu);
 int intel_svm_page_response(struct device *dev, struct iommu_fault_event *evt,
 			    struct iommu_page_response *msg);
 struct iommu_domain *intel_svm_domain_alloc(void);
@@ -887,8 +887,8 @@ extern const struct iommu_ops intel_iommu_ops;
 
 #ifdef CONFIG_INTEL_IOMMU
 extern int intel_iommu_sm;
-extern int iommu_calculate_agaw(struct intel_iommu *iommu);
-extern int iommu_calculate_max_sagaw(struct intel_iommu *iommu);
+int iommu_calculate_agaw(struct intel_iommu *iommu);
+int iommu_calculate_max_sagaw(struct intel_iommu *iommu);
 int ecmd_submit_sync(struct intel_iommu *iommu, u8 ecmd, u64 oa, u64 ob);
 
 static inline bool ecmd_has_pmu_essential(struct intel_iommu *iommu)