Coccinelle: Update information about the minimal version required

The naming convention of options has changed one year ago.
The options have been recently updated in the cocci file
and in scripts/coccicheck. This patch also adds this information
in the documentation.

Signed-off-by: Nicolas Palix <nicolas.palix@imag.fr>
Signed-off-by: Michal Marek <mmarek@suse.cz>