tls: recv: process_rx_list shouldn't use an offset with kvec

tls: recv: process_rx_list shouldn't use an offset with kvec

Only MSG_PEEK needs to copy from an offset during the final
process_rx_list call, because the bytes we copied at the beginning of
tls_sw_recvmsg were left on the rx_list. In the KVEC case, we removed
data from the rx_list as we were copying it, so there's no need to use
an offset, just like in the normal case.

Fixes: 692d7b5d1f91 ("tls: Fix recvmsg() to be able to peek across multiple records")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/e5487514f828e0347d2b92ca40002c62b58af73d.1711120964.git.sd@queasysnail.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>