sparc: Avoid -Wunused-but-set-parameter in clear_user_page()

The loop in clear_user_pages() iterates over all pages and calls
clear_user_page() for each of them. During the loop "vaddr" is modified.
However on sparc clear_user() is a macro which does not use "vaddr".
The compiler sees a variable which is modified but never used and emits
a warning for that:

	include/linux/highmem.h: In function 'clear_user_pages':
	include/linux/highmem.h:234:63: warning: parameter 'vaddr' set but not used [-Wunused-but-set-parameter=]
		static inline void clear_user_pages(void *addr, unsigned long vaddr,

Other architectures use an inline function for clear_user_page() which
avoids the warning. This is not possible on sparc, as
sparc_flush_page_to_ram() is not yet declared where clear_user_page() is
defined. Including cacheflush_32.h will trigger recursive and lots of
other issues.

So hide the warning with a cast to (void) instead.

While we are here, do the same for copy_user_page().

Fixes: 62a9f5a ("mm: introduce clear_pages() and clear_user_pages()")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Andreas Larsson <andreas@gaisler.com>

Author: t-8ch

arch/sparc/include/asm/page_32.h

@@ -20,10 +20,12 @@
 #define clear_user_page(addr, vaddr, page)	\
 	do { 	clear_page(addr);		\
 		sparc_flush_page_to_ram(page);	\
+		(void)(vaddr);			\
 	} while (0)
 #define copy_user_page(to, from, vaddr, page)	\
 	do {	copy_page(to, from);		\
 		sparc_flush_page_to_ram(page);	\
+		(void)(vaddr);			\
 	} while (0)
 
 /* The following structure is used to hold the physical