dm raid: Remove unnecessary negation of a shift in raid10_format_to_md_layout

When building with Clang + -Wtautological-constant-compare:

 drivers/md/dm-raid.c:619:8: warning: converting the result of '<<' to a
 boolean always evaluates to true [-Wtautological-constant-compare]
                 r = !RAID10_OFFSET;
                      ^
 drivers/md/dm-raid.c:517:28: note: expanded from macro 'RAID10_OFFSET'
 #define RAID10_OFFSET                   (1 << 16) /* stripes with data
 copies area adjacent on devices */
                                           ^
 1 warning generated.

Negating a non-zero number will always make it zero, which is the
default value of r in this function so this statement is unnecessary;
remove it so that clang no longer warns.

Link: https://github.com/ClangBuiltLinux/linux/issues/753Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-raid.c

@@ -620,7 +620,6 @@ static int raid10_format_to_md_layout(struct raid_set *rs,
 
 	} else if (algorithm == ALGORITHM_RAID10_FAR) {
 		f = copies;
-		r = !RAID10_OFFSET;
 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
 			r |= RAID10_USE_FAR_SETS;