[Bug Report]Sound: sound/core/hwdep.c undefined result by left shifting 1 by 31

[Changming Liu]

Hi Jaroslav, Takashi:
Greetings, I'm a first year PhD student who is interested in using UBSan for linux. 
After some experiments, I found that in sound/core/hwdep.c function snd_hwdep_dsp_load 
there might be an undefined behavior that might cause unexpected result.

More specifically, in this function,info was fetched from user space and,
info.index was checked if it's greater than or equal to 32.
If not then it's used as number of left shift bits to string literal 1.

The problem is, since string literal 1 is by default signed int, so 1 << 31 cannot be represented as a valid integer and
 the result might be undefined across different platforms. So I guess change 1 to 1U might help?

Due to the lack of knowledge of the interaction between this module and others, I'm not able to assess if 
this is critical or worth fixing. I'd appreciate if for your comment on this bug. This can help me understand UB a lot!

Looking forward to your response.

Best,
Changming Liu