checkpatch: don't warn on bitfield spaces around :

This test prevents code from being aligned around the : for easy visual
counting of bitfield lengths.

ie:
	int foo		: 1,
	int bar		: 2,
	int foobar	:29;

should be acceptable so remove the test.

Signed-off-by: Joe Perches <joe@perches.com>
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>