Implementation of Linux user emulation for Hexagon
Some common files modified in addition to new files in linux-user/hexagon

Acked-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <1612763186-18161-31-git-send-email-tsimpson@quicinc.com>
[rth: Fix termbits.h on review by Laurent]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>