em100: Add missing options to README

Add a few options to the README so it matches the usage output of the utility.

  -a|--start address:             only works with -d (E.g. -d file.bin -a 0x300000)
  -m|--address-mode MODE:         force 3 or 4 byte address mode
  -V|--set-voltage [1.8|3.3]      switch FPGA voltage
  -U|--update-files               update device (chip) and firmware database
  -C|--compatible                 enable compatibility mode (patch image for EM100Pro)

Change-Id: I40a9c5b3e978aa4343b98fe7136775355092dd85
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: https://review.coreboot.org/c/em100/+/40419
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
1 file changed