fix: enable CONFIG_PROC_CHILDREN for amd64 kernel

Fixes siderolabs/talos#8986

Signed-off-by: Andrey Smirnov <andrey.smirnov@siderolabs.com>

Author: smira

kernel/build/config-amd64

@@ -5474,7 +5474,7 @@ CONFIG_PROC_VMCORE=y
 # CONFIG_PROC_VMCORE_DEVICE_DUMP is not set
 CONFIG_PROC_SYSCTL=y
 CONFIG_PROC_PAGE_MONITOR=y
-# CONFIG_PROC_CHILDREN is not set
+CONFIG_PROC_CHILDREN=y
 CONFIG_PROC_PID_ARCH_STATUS=y
 CONFIG_KERNFS=y
 CONFIG_SYSFS=y