Benh points out that the msgs[0].flags entry never got initialized, and
since it's an automatic stack allocation, it could have any random
value, which is bad.
Rewrite the initializer to explicitly initialize all fields of the small
i2c_msg structure array we generate. Just to keep it all obvious, let's
handle msgs[1].buf in the same initializer while we're at it, instead of
initializing that one separately later.