EXA: Trace prepare/finish and log error on any OMAPPrepareAccess fail
EXA: Trace prepare/finish and log error on any OMAPPrepareAccess fail

Inspired by an error message added in:
(commit ae5a636895f5cebeba6c844c68ca78588fee70c2)
From linaro: git://git.linaro.org/arm/xorg/driver/xf86-video-armsoc.git

But adding a bit more info to error message, and logging any "failure",
not just ioctl fails (which are already reported in the omap_bo_cpu_prep
itself).

Signed-off-by: Daniel Kurtz <31914e832df1cd8e5daa417106c0c6f5297b27d7@chromium.org>

BUG=chromium:272670
TEST=build clean; verify armsoc driver loads successfully and ui comes up

Change-Id: Iab12ba29e813d13019ab4caa37f93031e5cc9abe
Reviewed-on: https://chromium-review.googlesource.com/168188
Reviewed-by: John Sheu <e133b36fa071c0f7efb4cebd35fa1371d3ae789d@chromium.org>
Reviewed-by: Daniel Kurtz <31914e832df1cd8e5daa417106c0c6f5297b27d7@chromium.org>
Tested-by: Daniel Kurtz <31914e832df1cd8e5daa417106c0c6f5297b27d7@chromium.org>
Commit-Queue: Daniel Kurtz <31914e832df1cd8e5daa417106c0c6f5297b27d7@chromium.org>

markyzq/armsoc-rockchip,markyzq/armsoc-rockchip