PCI: Unify PCI and normal DMA direction definitions

Current DMA direction definitions in pci-dma-compat.h and dma-direction.h
are mirrored in value.  Unify them to enhance readability and avoid
possible inconsistency.
Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Joey Zheng <yu.zheng@hxt-semitech.com>

include/linux/dma-direction.h

 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_DMA_DIRECTION_H
 #define _LINUX_DMA_DIRECTION_H
-/*
- * These definitions mirror those in pci.h, so they can be used
- * interchangeably with their PCI_ counterparts.
- */
+
 enum dma_data_direction {
 	DMA_BIDIRECTIONAL = 0,
 	DMA_TO_DEVICE = 1,
 	DMA_FROM_DEVICE = 2,
 	DMA_NONE = 3,
 };
+
 #endif

include/linux/pci-dma-compat.h

@@ -8,10 +8,10 @@
 #include <linux/dma-mapping.h>
 
 /* This defines the direction arg to the DMA mapping routines. */
-#define PCI_DMA_BIDIRECTIONAL	0
-#define PCI_DMA_TODEVICE	1
-#define PCI_DMA_FROMDEVICE	2
-#define PCI_DMA_NONE		3
+#define PCI_DMA_BIDIRECTIONAL	DMA_BIDIRECTIONAL
+#define PCI_DMA_TODEVICE	DMA_TO_DEVICE
+#define PCI_DMA_FROMDEVICE	DMA_FROM_DEVICE
+#define PCI_DMA_NONE		DMA_NONE
 
 static inline void *
 pci_alloc_consistent(struct pci_dev *hwdev, size_t size,