drm/vc4: Get the rid of DRM_ERROR()

DRM_ERROR() has been deprecated in favor of pr_err(). However, we
should prefer to use drm_err() whenever possible so we get device-
specific output with the error message. In error case of kcalloc,
we can simply drop DRM_ERROR(), because kcalloc already logs errors.

Suggested-by: Maíra Canal <mcanal@igalia.com>
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Maíra Canal <mcanal@igalia.com>
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240821214052.6800-4-wahrenst@gmx.net