kernel: poll: rename reserved 'signal' symbol

This symbol is reserved and usage of reserved symbols violates the
coding guidelines. (MISRA 21.2)

NAME
       signal - ANSI C signal handling

SYNOPSIS
       #include <signal.h>

       sighandler_t signal(int signum, sighandler_t handler);

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2 files changed