checkpatch: improve network block comment style checking

Some comment styles in net and drivers/net are flagged inappropriately.

Avoid proclaiming inline comments like:
	int a = b;	/* some comment */
and block comments like:
	/*********************
	 * some comment
	 ********************/
are defective.

Tested with
$ cat drivers/net/t.c
/* foo */

/*
 * foo
 */

/* foo
 */

/* foo
 * bar */

/****************************
 * some long block comment
 ***************************/

struct foo {
	int bar;	/* another test */
};
$

Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: David Miller <davem@davemloft.net>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>