checkpatch: suspect indent handle macro continuation

When ignoring a macro in the middle of a conditional, we need to ignore
the macro start and any continuation lines.

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>