sconfig: Allow strings in devicetree.cb

Currently you cannot assign a string to a register in devicetree because
the quotes are removed when parsing and the literal is assigned directly.

Add a parse option for two double-quotation marks to indicate a string
and return a quoted literal that can be assigned to a register with a
'const char *' type.

Example:

chip drivers/i2c/generic
  register "hid" = ""INT343B""
  register "uid" = "1"
  device i2c 15 on end
end

Change-Id: I621cde1f7547494a8035fbbab771f29522da1687
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/14787
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
1 file changed