checkpatch: extend line continuation test

Preprocessor directives and asm statements should be allowed to have a
line continuation.
Signed-off-by: NJoe Perches <joe@perches.com>
Tested-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -3009,10 +3009,12 @@ sub process {
 				}
 			}
 
-# check for line continuations outside of #defines
+# check for line continuations outside of #defines, preprocessor #, and asm
 
 		} else {
 			if ($prevline !~ /^..*\\$/ &&
+			    $line !~ /^\+\s*\#.*\\$/ &&		# preprocessor
+			    $line !~ /^\+.*\b(__asm__|asm)\b.*\\$/ &&	# asm
 			    $line =~ /^\+.*\\$/) {
 				WARN("LINE_CONTINUATIONS",
 				     "Avoid unnecessary line continuations\n" . $herecurr);