scripts: add checkpatch wrapper

scripts: add checkpatch wrapper

This script can be used to call checkpatch.pl from Linux with some
custom DPDK options.

The path to the original Linux script must be set in an environment
variable. A script is added to load any configuration variables
required by development tools from a file .develconfig, or
~/.config/dpdk/devel.config or /etc/dpdk/devel.config.

Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
v2:
- do not ignore COMPLEX_MACRO
- use option --no-tree to avoid silent failure
- add -q and -v options