Due to the initial confusion about MIPI_DSI_MODE_EOT_PACKET, properly
renamed to MIPI_DSI_MODE_NO_EOT_PACKET, reflecting its actual meaning,
both the DSI_TXRX_CON register setting for bit (HSTX_)DIS_EOT and the
later calculation for horizontal sync-active (HSA), back (HBP) and
front (HFP) porches got incorrect due to the logic being inverted.

This means that a number of settings were wrong because....:
 - DSI_TXRX_CON register setting: bit (HSTX_)DIS_EOT should be
   set in order to disable the End of Transmission packet;
 - Horizontal Sync and Back/Front porches: The delta used to
   calculate all of HSA, HBP and HFP should account for the
   additional EOT packet.

Before this change...
 - Bit (HSTX_)DIS_EOT was being set when EOT packet was enabled;
 - For HSA/HBP/HFP delta... all three were wrong, as words were
   added when EOT disabled, instead of when EOT packet enabled!

Invert the logic around flag MIPI_DSI_MODE_NO_EOT_PACKET in the
MediaTek DSI driver to fix the aforementioned issues.

Fixes: 8b2b99fd ("drm/mediatek: dsi: Fine tune the line time caused by EOTp")
Fixes: c87d1c4b ("drm/mediatek: dsi: Use symbolized register definition")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Tested-by: Michael Walle <mwalle@kernel.org>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20230523104234.7849-1-angelogioacchino.delregno@collabora.com/Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>