drm/meson: use vclk_freq instead of pixel_freq in debug print

meson_vclk_vic_supported_freq() has a debug print which includes the
pixel freq. However, within the whole function the pixel freq is
irrelevant, other than checking the end of the params array. Switch to
printing the vclk_freq which is being compared / matched against the
inputs to the function to avoid confusion when analyzing error reports
from users.

Fixes: e5fab2ec ("drm/meson: vclk: add support for YUV420 setup")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20250606221031.3419353-1-martin.blumenstingl@googlemail.com