kern-tools: refresh and make dash compliant

kern-tools: refresh and make dash compliant

The separately packaged merge_config.sh in the kern-tools package was
missing upstream fixes, and in particular a change that ensures it is
dash compatible.

By grabbing that upstream commit and rebasing the existing patches on
top of the new baseline, we are up to date and working on systems
where /bin/sh is dash.

[YOCTO #4473]

(From OE-Core rev: 681bcd2783e100dd2882273f28f16ef118161e89)

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>