arm64: dts: mediatek: Declare drive-strength numerically

arm64: dts: mediatek: Declare drive-strength numerically

On some devicetrees, the drive-strength property gets assigned a
MTK_DRIVE_(x)_mA definition, which matches with (x).

For example, MTK_DRIVE_8mA equals to 8 and MTK_DRIVE_30mA equals
to 30.

Also keeping in mind that the drive-strength property is, by
(binding) definition, taking a number in milliamperes unit,
change all devicetrees to avoid the usage of any MTK_DRIVE_(x)
definition.

Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20240620101656.1096374-2-angelogioacchino.delregno@collabora.com
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>