The current help text for rpi-eeprom-config are unclear. This PR changes them so that the help text matches what the tool does and what each parameter specifies. The man page, automatically derived from the help text, is also fixed.
Update the rpi-eeprom-config tool to accept config files of up to
2024 byte. The config section has a 24byte header so the section is
always <= 2KiB.
This allows a reasonably large user-data section in the config file
accessible via 'vcgencmd bootloader_config' as an alternative to
customer OTP data.
N.B. The vcgencmd uses a single VCHIQ message which is limited to
4092 bytes. Setting a 2KiB limit here gives room for user-data plus
some spare space for future config expansion before an VCHIQ bulk
message or an extra EEPROM 4KiB page is required.
If the size of bootconf.txt is reduced then set the unused data
to all ones instead of leaving garbage at the end. The EEPROM
header contains the actual file but this makes it easier to
verify the image and makes overreads more obvious.
