net: ipv6: fix wrong ping_v6_sendmsg return value

ping_v6_sendmsg currently returns 0 on success. It should return
the number of bytes written instead.

CRs-Fixed: 573548
Change-Id: I82b7d3a37ba91ad24e6dbd97a4880745ce16ad31
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Git-commit: fbfe80c890a1dc521d0b629b870e32fcffff0da5
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>