namei: Improve hash mixing if CONFIG_DCACHE_WORD_ACCESS

The hash mixing between adding the next 64 bits of name
was just a bit weak.

Replaced with a still very fast but slightly more effective
mixing function.

Signed-off-by: George Spelvin <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
1 file changed