[Intel-gfx] About the wait_for() macro in intel_drv.h

[Zhi Wang]

Hi Gurus:
    Recently we found that the wait_for() marco in intel_drv.h looks
will cause dead lock. wait_for() macro will try to wait jiffies change
in a condition check loop, but when local cpu interrupt is disabled, it
seems the jiffies will never change under a uni-processor environment.
And in forcewake_get/put path, the local cpu irq will always be disabled
by a spin_lock_irqsave() in genX_read() and some genX_write(), So if the
change of HW register (e.g. forcewake ack) turns slow at this time,
there should be a dead lock here I think?

Thanks,
Zhi.