Enable PAM systemwide

PAM is good, and since Netopeer got support for PAM some time ago,
there's no reason to keep working with the PAM-less "minimal" system
that we've used up to now. Also, having PAM will make it easier to
enable Radius and/or TACACS+ later on.

Change-Id: I5f230a0ae99ceb0af7a6be6e351d0f178638668a
diff --git a/configs/czechlight_clearfog_defconfig b/configs/czechlight_clearfog_defconfig
index d36f71b..84b9361 100644
--- a/configs/czechlight_clearfog_defconfig
+++ b/configs/czechlight_clearfog_defconfig
@@ -54,6 +54,7 @@
 BR2_PACKAGE_NETOPEER2_CLI=y
 BR2_PACKAGE_ELFUTILS=y
 BR2_PACKAGE_LIBUNWIND=y
+BR2_PACKAGE_LINUX_PAM=y
 BR2_PACKAGE_ETHTOOL=y
 BR2_PACKAGE_IPROUTE2=y
 BR2_PACKAGE_MSTPD=y