drm: Eliminate magic I2C frobbing when reading EDID

This code depends on the underlying I2C adapter using the bit-banging algo,
which may not be the case. If specific encoders require this mechanism, they
should build a custom I2C algo that implements this workaround, rather than
having it in the general path.

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>