message: linker: make sram origin symbol
  This allows elf2tab to determine what the start of RAM address is.
diff: @@ -88,6 +88,15 @@ SECTIONS {
  /* Application stack */
  .stack (NOLOAD) :
  {
  + /* elf2tab requires that the `_SRAM_ORIGIN` symbol be present to
  + * mark the first address in the SRAM memory. Since ELF files do
  + * not really need to specify this address as they only care about
  + * loading into flash, we need to manually mark this address for
  + * elf2tab. elf2tab will use it to add a fixed address header in the
  + * TBF header if needed.
  + */
  + _SRAM_ORIGIN = .;
  +
  . = . + STACK_SIZE;
  _stack_top_unaligned = .;
  