powerpc/64s: Remove irq mask workaround in accumulate_stolen_time()

The caller has been moved to C after irq soft-mask state has been
reconciled, and Linux IRQs have been marked as disabled, so this no
longer needs to play games with IRQ internals.

Fixes: 68b34588 ("powerpc/64/sycall: Implement syscall entry/exit logic in C")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210623022924.704645-1-npiggin@gmail.com

arch/powerpc/kernel/time.c

@@ -231,24 +231,13 @@ static u64 scan_dispatch_log(u64 stop_tb)
 void notrace accumulate_stolen_time(void)
 {
 	u64 sst, ust;
-	unsigned long save_irq_soft_mask = irq_soft_mask_return();
 	struct cpu_accounting_data *acct = &local_paca->accounting;
 
-	/* We are called early in the exception entry, before
-	 * soft/hard_enabled are sync'ed to the expected state
-	 * for the exception. We are hard disabled but the PACA
-	 * needs to reflect that so various debug stuff doesn't
-	 * complain
-	 */
-	irq_soft_mask_set(IRQS_DISABLED);
-
 	sst = scan_dispatch_log(acct->starttime_user);
 	ust = scan_dispatch_log(acct->starttime);
 	acct->stime -= sst;
 	acct->utime -= ust;
 	acct->steal_time += ust + sst;
-
-	irq_soft_mask_set(save_irq_soft_mask);
 }
 
 static inline u64 calculate_stolen_time(u64 stop_tb)