Added two more functions in DRAM Stress test

[#1]

Added two functions in DDR_Stress_Tester V1.0.2, find the attachment for the details.

1. Check the actual boot mode settings in H/W target board

2. Add test option for bit flip and bit spread walking test

[m_c]

Very useful !!!

[seanchen]

This method is very useful!!

Can check HW boot mode setting.

Thanks a lot.

[weikeng-jimmy]

Thanks for your update !

[carolchen]

It is good tool for share. Thanks!!!

[Danube]

It's good tool for customer using ...