[modify] if ... else if constructs to be terminated with an else clause, which other option is invalid and delete surplus space.

1. Improve code readability,  unify the variable name  in functions "rt_hw_interrupt_enable(level);" and "rt_hw_interrupt_enable(level);",
so changed variable  "temp" to "level";

Signed-off-by: NCliff Chen <cliff.chen@rock-chips.com>

程序的分支逻辑出错。
详见修改。

rt_realloc may cause <lfree> change, if we don't change <lfree> timely, it may cause memory leakage

Signed-off-by: Nlihui <leehui_hrbeu71102@163.com>

Signed-off-by: Nsuhui <3164683437@qq.com>