parisc: Change kunmap macro to static inline function

Change kunmap macro to static inline function to fix build error
compiling drivers/base/dma-buf.c.

Without the change, the following error can occur:

   CC      drivers/base/dma-buf.o
drivers/base/dma-buf.c: In function 'dma_buf_kunmap':
drivers/base/dma-buf.c:427:46:
error: macro "kunmap" passed 3 arguments, but takes just 1

I believe parisc is the only arch to implement kunmap using a macro.
Signed-off-by: NJohn David Anglin <dave.anglin@bell.net>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: NHelge Deller <deller@gmx.de>

arch/parisc/include/asm/cacheflush.h

@@ -140,7 +140,10 @@ static inline void *kmap(struct page *page)
 	return page_address(page);
 }
 
-#define kunmap(page)			kunmap_parisc(page_address(page))
+static inline void kunmap(struct page *page)
+{
+	kunmap_parisc(page_address(page));
+}
 
 static inline void *kmap_atomic(struct page *page)
 {