coccinelle: misc: minmax: suppress patch generation for err returns

There is a standard idiom for "if 'ret' holds an error, return it":
	return ret < 0 ? ret : 0;

Developers prefer to keep the things as they are because stylistic
change to "return min(ret, 0);" breaks readability.

Let's suppress automatic generation for this type of patches.

Signed-off-by: Denis Efremov <efremov@linux.com>