drm/arm/malidp: Silence informational message

When checking for unsupported expect an error is printed every time.
This spams the log for platforms where this is expected, e.g. ls1028a
having a Vivante (etnaviv) GPU and Mali display processor.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://lore.kernel.org/r/20250523064042.3275926-1-alexander.stein@ew.tq-group.com