Create a signal-common.h for future use by these new files
and use it in the existing signal.c
Signed-off-by: NLaurent Vivier <laurent@vivier.eu>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Message-Id: <20180424192635.6027-2-laurent@vivier.eu>