devtool: Allow disabling make parallelism on build command
Through -s/--disable-parallel-make, the user can turn off parallelism
on the make tool. This can be useful when debuging race condition issues.
In order to set PARALLEL_MAKE = "" a post-config file created and then
passed into the build.
[YOCTO #7589]
Signed-off-by: Leonardo Sandoval <leonardo.sandoval.gonzalez@linux.intel.com> Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
