checkpatch: suppress mailback option in conf file

Suppress mailback conf to allow to use the -g parameter.
With the -g option it is possible to check coding style for multi
commits in the git tree without extracting them.
For instance the './scripts/checkpatch.pl --strict --git HEAD-4' command
checks the last 4 patches of the current branch.

Signed-off-by: Arnaud Pouliquen <[email protected]>

Author: arnopo

.checkpatch.conf

@@ -1,4 +1,3 @@
---mailback
 --emacs
 --summary-file
 --show-types