[stk-webcam] change constants to work better on FreeBSD

[Buganini]

Suggested by hselasky@xxxxxxxxxxx, tested by me on FreeBSD.
With original value it hangs a lot.

I dont fully understand background knowledge,
it's said that the default value is not enough for high speed transfer.


--Buganini

Attachment: stk-webcam.h.patch
Description: Binary data