kbuild: do not add "selinux" to subdir- twice

scripts/Makefile adds "selinux" to subdir-y or subdir- twice.

  subdir-$(CONFIG_MODVERSIONS) += genksyms
  subdir-y                     += mod
  subdir-$(CONFIG_SECURITY_SELINUX) += selinux    <--- here
  subdir-$(CONFIG_DTC)         += dtc

  # Let clean descend into subdirs
  subdir- += basic kconfig package selinux        <--- again

The latter is redundant.
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

scripts/Makefile

@@ -39,4 +39,4 @@ subdir-$(CONFIG_SECURITY_SELINUX) += selinux
 subdir-$(CONFIG_DTC)         += dtc
 
 # Let clean descend into subdirs
-subdir-	+= basic kconfig package selinux
+subdir-	+= basic kconfig package