gcc: Convert do_headerfix into a definitive patch

gcc: Convert do_headerfix into a definitive patch

do_headerfix task is essentially editing configuration
headers in sources which can well be maintained as a
patch which is easier to spot errors (if any) than
dynamically edited source tree

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>