checkpatch: add checks for question mark and colon spacing

Add checks for the question mark colon operator spacing, and also check
the other uses of colon.  Colon means a number of things:

 - it introduces the else part of the ?: operator,
 - it terminates a goto label,
 - it terminates the case value,
 - it separates the identifier from the bit size on bit fields, and
 - it is used to introduce option types in asm().

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>