[Patch]Add a function kernel_string2 for copy non-0-terminated string with fixed length from kernel space at given address.

[Stone, Joshua I]

Cai Fei wrote:
> Thanks for your suggestion. I have changed it to kernel_string_n.
> Also, I have tested it on RHEL5(IA64).

I meant an automated test, so that it gets tested and verified on all
platforms.  The addition of a length parameter creates several corner
cases that need to work safely. (length <= 0, length > MAXSTRINGLEN,
etc.)

Josh