Revert r336326.

[markj]

Summary

On my Dell Latitude, the suspend/resume issue caused by ig4 appears to
be resolved by r342170. In particular, while debugging the issue I
found that ig4iic_pci0 and vgapci0 share an interrupt, and ig4iic_intr() was
being called after the device entered D3, so the read of IG4_REG_I2C_STA
returned 0xffffffff and we would enter an infinite loop as a result.

Test Plan

Suspend/resume on my laptop now works with ig4.ko. I happened to be
debugging the issue at the same time that r342170 was committed, so
based on the symptoms I'm fairly confident that r342170 addressed the
root cause.