checkpatch: complex macro should allow the empty do while loop

It is common to stub out a function as below, this is triggering a complex
macro format incorrectly.  Sort this out:

    #define cma_early_regions_reserve(reserve)   do { } while (0)

Signed-off-by: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -2838,7 +2838,7 @@ sub process {
 			    $dstat !~ /^(?:$Ident|-?$Constant)$/ &&			# 10 // foo()
 			    $dstat !~ /$exceptions/ &&
 			    $dstat !~ /^\.$Ident\s*=/ &&				# .foo =
-			    $dstat !~ /^do\s*$Constant\s*while\s*$Constant;$/ &&	# do {...} while (...);
+			    $dstat !~ /^do\s*$Constant\s*while\s*$Constant;?$/ &&	# do {...} while (...); // do {...} while (...)
 			    $dstat !~ /^for\s*$Constant$/ &&				# for (...)
 			    $dstat !~ /^for\s*$Constant\s+(?:$Ident|-?$Constant)$/ &&	# for (...) bar()
 			    $dstat !~ /^do\s*{/ &&					# do {...