linux-user: fix TARGET_NSIG and _NSIG uses

Valid signal numbers are between 1 (SIGHUP) and SIGRTMAX.

System includes define _NSIG to SIGRTMAX + 1, but
QEMU (like kernel) defines TARGET_NSIG to TARGET_SIGRTMAX.

Fix all the checks involving the signal range.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Taylor Simpson <tsimpson@quicinc.com>
Message-Id: <20200212125658.644558-4-laurent@vivier.eu>
1 file changed