Fixed CMSIS-RTOS RTX for Cortex-A9

I fixed a bug as below.
A bug occured in CMSIS-RTOS RTX for Cortex-A9 when the build option is -O3.
Merge pull request #700 from masaohamanaka/master

[RZ_A1H]Fixed a bug of CMSIS-RTOS RTX for Cortex-A9