Staging: lustre: lnet: selftest: Made a function static.

The following patch makes a function static as it was not used by other
files.
The patch fixes the warning:
WARNING: symbol 'brw_check_page' was not declared. Should it be static?

The above warning was reported by sparse.
Signed-off-by: Heena Sirwani <heenasirwani@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lnet/selftest/brw_test.c

@@ -178,7 +178,7 @@ brw_fill_page(struct page *pg, int pattern, __u64 magic)
 	return;
 }
 
-int
+static int
 brw_check_page(struct page *pg, int pattern, __u64 magic)
 {
 	char  *addr = page_address(pg);