drm/msm: Check if target supports crash dump capture

This patch simply checks first to see if the target can support crash dump
capture before proceeding.

Signed-off-by: Sharat Masetty <smasetty@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>