MIPS: Add support for fine granularity task level IRQ time accounting

With sched_clock being ready, it makes sense to add the option of IRQ time
accounting -- When we have a fast enough sched_clock, IRQ time accounting
will be enabled (see sched_clock_register).

Signed-off-by: Deng-Cheng Zhu <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Patchwork: https://patchwork.linux-mips.org/patch/9489/
Signed-off-by: Ralf Baechle <[e-mail]>

arch/mips/Kconfig

···
 	select ARCH_BINFMT_ELF_STATE
 	select SYSCTL_EXCEPTION_TRACE
 	select HAVE_VIRT_CPU_ACCOUNTING_GEN
+	select HAVE_IRQ_TIME_ACCOUNTING
 
 menu "Machine selection"