config-mpi: Reenable /proc/PID/io

/proc/PID/io depend on TASK_IO_ACCOUNTING -> TASK_XACCT ->
TASKSTATS.

TASKSTATS has been autoselected by KVM until 63b3f96 ("kvm: Select
SCHED_INFO instead of TASK_DELAY_ACCT ") which landed in v5.14.

To keep this feature, select TASK_IO_ACCOUNTING and its dependencies
explicitly.

config-mpi

@@ -9,6 +9,9 @@ CONFIG_BPF_SYSCALL=y
 CONFIG_PREEMPT_VOLUNTARY=y
 CONFIG_BSD_PROCESS_ACCT=y
 CONFIG_BSD_PROCESS_ACCT_V3=y
+CONFIG_TASKSTATS=y
+CONFIG_TASK_XACCT=y
+CONFIG_TASK_IO_ACCOUNTING=y
 CONFIG_PSI=y
 CONFIG_IKCONFIG=y
 CONFIG_IKCONFIG_PROC=y