checkpatch: ignore networking block comment style first lines in file

checkpatch: ignore networking block comment style first lines in file

It's very common to have normal block comments for the initial comments
of a file description preface.

So for files in drivers/net and net/ don't emit a warning when the first
comment block in the file uses the normal block comment style and not
the networking block comment style.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>