focaltech: remove support for auto upgrade and included fw file

to upgrade the firmware, do:

cd /sys/class/input/event0/device/device
cat fts_fw_version
echo /home/purism/FT8006P_Reference_C001_P001_V0x03_L0x02_20200305_all.bin > fts_upgrade_bin
cat fts_fw_version
2 jobs for firmware_upgrade
in 49 minutes and 52 seconds, using 0.0 compute credits, and was queued for 1 second
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