drm/msm/dp: avoid sending segment_address command for segment-0

Some non-compliant monitors report DP_AUX_ERR_ADDR errors on
sending segment_address AUX write command for segment-0. Hence,
avoid sending this command since the default segment for EDID read
is segment-0 even though it is not specified.

Change-Id: I0777a6f1579456316630e08d836ce5f3f6bbf47b
Signed-off-by: Padmanabhan Komanduru <pkomandu@codeaurora.org>