[IB] mthca: Use enum in mthca_alloc_db() prototype

Make the type parameter of mthca_alloc_db() be an enum mthca_db_type
instead of an int.  This doesn't have any practical effect but
documents the functions a little better.
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mthca/mthca_memfree.c

@@ -487,7 +487,8 @@ void mthca_cleanup_user_db_tab(struct mthca_dev *dev, struct mthca_uar *uar,
 	}
 }
 
-int mthca_alloc_db(struct mthca_dev *dev, int type, u32 qn, __be32 **db)
+int mthca_alloc_db(struct mthca_dev *dev, enum mthca_db_type type,
+		   u32 qn, __be32 **db)
 {
 	int group;
 	int start, end, dir;

drivers/infiniband/hw/mthca/mthca_memfree.h

@@ -173,7 +173,8 @@ void mthca_cleanup_user_db_tab(struct mthca_dev *dev, struct mthca_uar *uar,
 
 int mthca_init_db_tab(struct mthca_dev *dev);
 void mthca_cleanup_db_tab(struct mthca_dev *dev);
-int mthca_alloc_db(struct mthca_dev *dev, int type, u32 qn, __be32 **db);
+int mthca_alloc_db(struct mthca_dev *dev, enum mthca_db_type type,
+		   u32 qn, __be32 **db);
 void mthca_free_db(struct mthca_dev *dev, int type, int db_index);
 
 #endif /* MTHCA_MEMFREE_H */