tests/kms_plane_scaling: Move get_num_scalers to a function, v2.

The number of scalers can depend on the pipe, so require at least 1
scaler before running any subtests.

Changes since v1:
- More closely match kernel implementation. (Mika)

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
1 file changed