nvmem: mtk-efuse: Support postprocessing for GPU speed binning data

nvmem: mtk-efuse: Support postprocessing for GPU speed binning data

On some MediaTek SoCs GPU speed binning data is available for read
in the SoC's eFuse array but it has a format that is incompatible
with what the OPP API expects, as we read a number from 0 to 7 but
opp-supported-hw is expecting a bitmask to enable an OPP entry:
being what we read limited to 0-7, it's straightforward to simply
convert the value to BIT(value) as a post-processing action.

So, introduce post-processing support and enable it by evaluating
the newly introduced platform data's `uses_post_processing` member,
currently enabled only for MT8186.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-28-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>