cgroup/dmem: Select PAGE_COUNTER

The dmem cgroup the page counting API implemented behing the
PAGE_COUNTER kconfig option. However, it doesn't select it, resulting in
potential build breakages. Select PAGE_COUNTER.

Fixes: b168ed458d ("kernel/cgroup: Add "dmem" memory accounting cgroup")
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Acked-by: Tejun Heo <[email protected]>
Reviewed-by: Simona Vetter <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Maxime Ripard <[email protected]>

init/Kconfig

@@ -1139,6 +1139,7 @@ config CGROUP_RDMA
 
 config CGROUP_DMEM
 	bool "Device memory controller (DMEM)"
+	select PAGE_COUNTER
 	help
 	  The DMEM controller allows compatible devices to restrict device
 	  memory usage based on the cgroup hierarchy.