Hexagon (target/hexagon) Change decision to set pkt_has_store_s[01]

Hexagon (target/hexagon) Change decision to set pkt_has_store_s[01]

We have found cases where pkt_has_store_s[01] is set incorrectly.
This leads to generating an unnecessary store that is left over
from a previous packet.

Add an attribute to determine if an instruction is a scalar store
The attribute is attached to the fSTORE macro (hex_common.py)
Update the logic in decode.c that sets pkt_has_store_s[01]

Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220920080746.26791-4-tsimpson@quicinc.com>