kernel-doc: add support for ____cacheline_aligned attribute

Subroutine dump_struct uses type attributes to check if the struct
syntax is valid. Then, it removes all attributes before using it for
output. `____cacheline_aligned` is an attribute that is
not included in both steps. Add it, since it is used by kernel structs.

Based on previous patch to add ____cacheline_aligned_in_smp.
Motivated by patches to reorder this attribute to before the
variable name.   Whilst we could do that in all cases, that would
be a massive change and it is more common in the kernel to place
this particular attribute after the variable name. A quick grep
suggests approximately 400 instances of which 341 have this
attribute just before a semicolon and hence after the variable name.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200910185415.653139-1-jic23@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

scripts/kernel-doc

@@ -1083,7 +1083,7 @@ sub dump_struct($$) {
     my $x = shift;
     my $file = shift;
 
-    if ($x =~ /(struct|union)\s+(\w+)\s*\{(.*)\}(\s*(__packed|__aligned|____cacheline_aligned_in_smp|__attribute__\s*\(\([a-z0-9,_\s\(\)]*\)\)))*/) {
+    if ($x =~ /(struct|union)\s+(\w+)\s*\{(.*)\}(\s*(__packed|__aligned|____cacheline_aligned_in_smp|____cacheline_aligned|__attribute__\s*\(\([a-z0-9,_\s\(\)]*\)\)))*/) {
 	my $decl_type = $1;
 	$declaration_name = $2;
 	my $members = $3;
@@ -1099,6 +1099,7 @@ sub dump_struct($$) {
 	$members =~ s/\s*__packed\s*/ /gos;
 	$members =~ s/\s*CRYPTO_MINALIGN_ATTR/ /gos;
 	$members =~ s/\s*____cacheline_aligned_in_smp/ /gos;
+	$members =~ s/\s*____cacheline_aligned/ /gos;
 
 	# replace DECLARE_BITMAP
 	$members =~ s/__ETHTOOL_DECLARE_LINK_MODE_MASK\s*\(([^\)]+)\)/DECLARE_BITMAP($1, __ETHTOOL_LINK_MODE_MASK_NBITS)/gos;