From the MEDIA_VFE_STATE docs:

   "Starting with this configuration, the Maximum Number of Threads must
    be set to (#EU * 8) for GPGPU dispatches.

    Although there are only 7 threads per EU in the configuration, the
    FFTID is calculated as if there are 8 threads per EU, which in turn
    requires a larger amount of Scratch Space to be allocated by the
    driver."

It's pretty clear that we need to increase this for scratch address
calculations, because the FFTID has a certain bit-pattern.  The quote
above seems to indicate that we should increase the actual thread count
programmed in MEDIA_VFE_STATE as well, but we think the intention is to
only bump the scratch space.

Fixes GPU hangs in Bioshock Infinite and Synmark's CSDof on Icelake 8x8.

Fixes: 5ac804bd

 ("intel: Add a preliminary device for Ice Lake")
Reviewed-by: Matt Turner <mattst88@gmail.com>