drm/panfrost: Drop duplicated Mediatek supplies arrays

drm/panfrost: Drop duplicated Mediatek supplies arrays

In the panfrost driver, the platform data of several Mediatek SoC
declares and uses custom supplies array definitions
(mediatek_mt8192_supplies, mediatek_mt8183_b_supplies), that are the
same as default_supplies (used by default platform data).

So drop these duplicated definitions and use default_supplies instead.
Also, rename mediatek_mt8183_supplies to a more generic name too
(legacy_supplies).

Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20250509-mt8370-enable-gpu-v6-2-2833888cb1d3@collabora.com