drm/msm: Fix error return code in msm_drm_init()

drm/msm: Fix error return code in msm_drm_init()

Fix to return a negative error code from the error handling case instead
of 0, as done elsewhere in this function.

Fixes: 8daeba87966d ("drm/msm: validate display and event threads")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20210508022836.1777-1-thunder.leizhen@huawei.com
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>