powerpc: Disable DAWR on POWER9 via CPU feature quirk

This disables the DAWR on all POWER9 CPUs via cpu feature quirk.

Using the DAWR on POWER9 can cause xstops, hence we need to disable
it.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/dt_cpu_ftrs.c

@@ -713,6 +713,9 @@ static __init void cpufeatures_cpu_quirks(void)
 	else if ((version & 0xffffefff) == 0x004e0202)
 		cur_cpu_spec->cpu_features |= CPU_FTR_P9_TM_HV_ASSIST |
 			CPU_FTR_P9_TM_XER_SO_BUG;
+
+	if ((version & 0xffff0000) == 0x004e0000)
+		cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR);
 }
 
 static void __init cpufeatures_setup_finished(void)