package/cgroupfs-mount: tweak the kernel config

When it was introduced in 2016 with commit 0e1547a87cfd (cgroupfs-mount:
new package), we did not yet have the infrastructure for package to set
kernel config options, which only came 4 years later with commit
0aed4c2dae76 (linux: allow packages to set kernel config options).

So at that time, the requirements for cgroupfs-mount were documented in
the help for the Kconfig symbol.

But now that we do have the infrastructure in place, actually use it to
set the required options, and drop the list from the Kconfig entry (that
would be duplication, prone to bit-rot with time, and other packages do
not document their requirements in Kconfig, they just use the infra to
set the options).

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/cgroupfs-mount/Config.in

@@ -4,16 +4,6 @@ config BR2_PACKAGE_CGROUPFS_MOUNT
 	help
 	  cgroupfs mount and umount scripts.
 
-	  requires a Linux kernel >= 3.0 with the following options
-	  enabled:
-
-	  - CONFIG_BLK_CGROUP
-	  - CONFIG_CGROUPS
-	  - CONFIG_CGROUP_CPUACCT
-	  - CONFIG_CGROUP_DEVICE
-	  - CONFIG_CGROUP_FREEZER
-	  - CONFIG_CGROUP_WRITEBACK
-	  - CONFIG_CGROUP_SCHED
-	  - CONFIG_CGROUP_PIDS
+	  Requires a Linux kernel >= 3.0
 
 	  https://github.com/tianon/cgroupfs-mount

package/cgroupfs-mount/cgroupfs-mount.mk

@@ -10,6 +10,17 @@ CGROUPFS_MOUNT_LICENSE = GPL-3.0+
 CGROUPFS_MOUNT_LICENSE_FILES = debian/copyright
 CGROUPFS_MOUNT_CPE_ID_VALID = YES
 
+define CGROUPFS_MOUNT_LINUX_CONFIG_FIXUPS
+	$(call KCONFIG_ENABLE_OPT,CONFIG_BLK_CGROUP)
+	$(call KCONFIG_ENABLE_OPT,CONFIG_CGROUPS)
+	$(call KCONFIG_ENABLE_OPT,CONFIG_CGROUP_CPUACCT)
+	$(call KCONFIG_ENABLE_OPT,CONFIG_CGROUP_DEVICE)
+	$(call KCONFIG_ENABLE_OPT,CONFIG_CGROUP_FREEZER)
+	$(call KCONFIG_ENABLE_OPT,CONFIG_CGROUP_WRITEBACK)
+	$(call KCONFIG_ENABLE_OPT,CONFIG_CGROUP_SCHED)
+	$(call KCONFIG_ENABLE_OPT,CONFIG_CGROUP_PIDS)
+endef
+
 define CGROUPFS_MOUNT_INSTALL_TARGET_CMDS
 	$(INSTALL) -D -m 0755 $(@D)/cgroupfs-mount $(TARGET_DIR)/usr/bin/cgroupfs-mount
 	$(INSTALL) -D -m 0755 $(@D)/cgroupfs-umount $(TARGET_DIR)/usr/bin/cgroupfs-umount