[media] dibusb-common: Don't use dynamic static allocation
Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:
drivers/media/usb/dvb-usb/dibusb-common.c:124:1: warning: 'dibusb_i2c_msg' uses dynamic stack allocation [enabled by default]
Instead, let's enforce a limit for the buffer to be the max size of
a control URB payload data (64 bytes).