Add a target to use the Coccinelle checker

A 'coccicheck' target is added. It can be called with four different
modes. Each one generates a different kind of output, i.e. context,
patch, org, report, according to the corresponding mode to be
activated.

The new target calls the 'coccicheck' front-end in the 'scripts'
directory with the MODE argument. Every SmPL file in the
subdirectories of 'scripts/coccinelle' is then given to the front-end
and applied to the entire source tree.

The four modes behave as follows:

'report' generates a list in the following format:
  file:line:column-column: message

'patch' proposes a fix, when possible.

'context' highlights lines of interest and their context in a
diff-like style. Lines of interest are indicated with '-'.

'org' generates a report in the Org mode format of Emacs.

Signed-off-by: Nicolas Palix <npalix@diku.dk>
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>