powerpc/powernv: Add debugfs file to grab opalv3 trace data

From: Rusty Russell <[email protected]>

This adds files in debugfs that can be used to retrieve the OPALv3 firmware "live binary traces" which can then be parsed using a userspace tool.

---
 arch/powerpc/platforms/powernv/Makefile           |   2 +-
 arch/powerpc/platforms/powernv/opal-trace-types.h |  58 +++++++
 arch/powerpc/platforms/powernv/opal-trace.c       | 183 ++++++++++++++++++++++
 3 files changed, 242 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/platforms/powernv/opal-trace-types.h
 create mode 100644 arch/powerpc/platforms/powernv/opal-trace.c

index f5d4149..e34a28d 100644
@@ -2,7 +2,7 @@ obj-y			+= setup.o opal-takeover.o opal-wrappers.o opal.o opal-async.o
 obj-y			+= opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o opal-sysparam.o
 obj-y			+= rng.o opal-dump.o opal-elog.o opal-sensor.o opal-msglog.o
 obj-y			+= subcore.o subcore-asm.o
-
+obj-$(CONFIG_DEBUG_FS)	+= opal-trace.o
 obj-$(CONFIG_SMP)	+= smp.o
 obj-$(CONFIG_PCI)	+= pci.o pci-p5ioc2.o pci-ioda.o
 obj-$(CONFIG_EEH)	+= eeh-ioda.o eeh-powernv.o