Hexagon (target/hexagon) Only use branch_taken when packet has multi cof

Hexagon (target/hexagon) Only use branch_taken when packet has multi cof

When a packet has more than one change-of-flow instruction, only the first
one to branch is considered.  We use the branch_taken variable to keep
track of this.

However, when there is a single cof instruction, we don't need the same
amount of bookkeeping.

We add the pkt_has_multi_cof member to the Packet structure, and pass this
information to the needed functions.

When there is a generated helper function with cof, the generator will
pass this pkt_has_multi_cof as a runtime value.

Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Message-Id: <20221108162906.3166-5-tsimpson@quicinc.com>