Hexagon (tests/tcg/hexagon) Fix alignment in load_unpack.c

The increment used in :brev tests was causing unaligned addresses
Change the increment and the relevant expected values

Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220718230320.24444-3-tsimpson@quicinc.com>