platform:x86: Add Intel Telemetry Debugfs interfaces

BugLink: http://bugs.launchpad.net/bugs/1520457

This implements debugfs interfaces for reading the telemetry
samples from SSRAM and configuring firmware trace verbosity.
Interface created under /sys/kernel/debug/telemetry
soc_states: SoC Device and Low Power States
pss_info: Info from the Primary SubSystem
ioss_info: Info from IO SubSusytem
pss_trace_verbosity: Read/Modify PSS F/W trace verbosity
ioss_trace_verbosity: Read/Modify IOSS F/W trace verbosity.
Signed-off-by: Souvik Kumar Chakravarty <souvik.k.chakravarty@intel.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
(cherry picked from commit 87bee290)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

MAINTAINERS

@@ -5720,6 +5720,7 @@ S:	Maintained
 F:	drivers/platform/x86/intel_telemetry_core.c
 F:	arch/x86/include/asm/intel_telemetry.h
 F:	drivers/platform/x86/intel_telemetry_pltdrv.c
+F:	drivers/platform/x86/intel_telemetry_debugfs.c
 
 IOC3 ETHERNET DRIVER
 M:	Ralf Baechle <ralf@linux-mips.org>

drivers/platform/x86/Makefile

@@ -64,4 +64,5 @@ obj-$(CONFIG_INTEL_PMC_IPC)	+= intel_pmc_ipc.o
 obj-$(CONFIG_SURFACE_PRO3_BUTTON)	+= surfacepro3_button.o
 obj-$(CONFIG_INTEL_PUNIT_IPC)  += intel_punit_ipc.o
 obj-$(CONFIG_INTEL_TELEMETRY)	+= intel_telemetry_core.o \
-				   intel_telemetry_pltdrv.o
+				   intel_telemetry_pltdrv.o \
+				   intel_telemetry_debugfs.o