i2c: i801: Improve too small kill wait time in i801_check_post

In my tests terminating a transaction took about 25ms, what is
in line with the chip-internal timeout as described in 5.21.3.2
"Bus Time Out" in [0]. Therefore the 2ms delay is too low.
Instead of a fixed delay let's use i801_wait_intr() here,
this also facilitates the status handling.

This potential issue seems to have been existing forever, but as no
related problem is known, treat it as an improvement.

[0] Intel document #326776-003, 7 Series PCH datasheet

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/ad4ef645-5d03-4833-a0b6-f31f8fd06483@gmail.com