checkpatch: %Lx tests should hand %% as a literal

Ensure that we handle literal %'s correctly when adjacent to a %Lx.

	%Lx	bad
	%%Lx	good
	%%%Lx	bad

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>