drmmode_display: debug_modes should not be set explictly
drmmode_display: debug_modes should not be set explictly

The correct way to set debug_modes is via the ModeDebug option
in xorg.conf. We also don't want this debug printed by default.

Also, removed PrintEDID call since this is redundant and not
typically done inside the get_modes callback.

BUG=chromium-os:37139
TEST=Verified that Xorg.0.log is less verbose.
TEST=Verified that mode debug can be re-enabied as follows:

Add:

Option          "ModeDebug"                 "true"

To (Device section):

/etc/X11/xorg.conf.d/exynos.conf

Note: there is still a lot of mode debug in the logs but less than
before.

Change-Id: I85606aeabcc7654367fd5cac980a3e038c9ee8fe
Signed-off-by: Mandeep Singh Baines <19acf4ef1f391f4aab404dc5703cac3632e06f3a@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/39536
Reviewed-by: Sean Paul <f9352ecf3e2294bdb914c99cca8d12601acec118@chromium.org>

markyzq/armsoc-rockchip,markyzq/armsoc-rockchip