ipv6: White-space cleansing : Structure layouts

This patch makes no changes to the logic of the code but simply addresses
coding style issues as detected by checkpatch.

Both objdump and diff -w show no differences.

This patch addresses structure definitions, specifically it cleanses the brace
placement and replaces spaces with tabs in a few places.

Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>