Bitwise operations on signed integers are not defined, replace them with per-call checks. Reviewed-by: Peng Fan <peng.fan@nxp.com> Signed-off-by: Marek Vasut <marex@denx.de> Reviewed-by: Fabio Estevam <festevam@denx.de> Reviewed-by: Heiko Schocher <hs@denx.de>