dlm: <linux/dlm_plock.h> should be "unifdef"ed.

Given that <linux/dlm_plock.h> contains a conditional __KERNEL__ test,
it should be moved from header-y to unifdef-y.
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: David Teigland <teigland@redhat.com>

include/linux/Kbuild

@@ -105,7 +105,6 @@ header-y += ixjuser.h
 header-y += jffs2.h
 header-y += keyctl.h
 header-y += limits.h
-header-y += dlm_plock.h
 header-y += magic.h
 header-y += major.h
 header-y += matroxfb.h
@@ -190,6 +189,7 @@ unifdef-y += cyclades.h
 unifdef-y += dccp.h
 unifdef-y += dirent.h
 unifdef-y += dlm.h
+unifdef-y += dlm_plock.h
 unifdef-y += edd.h
 unifdef-y += elf.h
 unifdef-y += elfcore.h