msm: limits: A new LMH monitor driver

Add a new Limits management hardware (LMH) monitor driver.
The LMH hardware driver, which interacts with the LMH hardware
via a secure image like TZ or hypervisor should register all
the LMH sensors with this driver. LMH monitor driver in turn
registers the sensors with the thermal sysfs framework.

The LMH monitor driver, when notified of a hardware throttling
interrupt by the hardware driver, will read the throttling
intensity and notify the thermal sysfs framework when
thresholds are crossed.

If the LMH hardware is capable of supporting multiple operating
profiles, then it can register itself separately as LMH
profile device. LMH Monitor driver exposes APIs to get/set the
LMH profiles.

LMH monitor driver exposes the below debugfs interfaces.

/sys/kernel/debug/lmh_monitor/interrupt_poll_delay_msec
  - Configures the interrupt polling interval in the LMH
    monitor driver. This value can be used by the hardware
    driver also.
/sys/kernel/debug/lmh_monitor/hw_trace_enable
  - Enable/disable LMH trace
/sys/kernel/debug/lmh_monitor/hw_trace_interval
  - Interval in XO clock ticks for adding timestamp in the
    trace logs.
/sys/kernel/debug/lmh_monitor/lmh-profile/level
  - Set or get the current LMH operating profile
/sys/kernel/debug/lmh_monitor/lmh-profile/total_levels
  - Total operating profile levels supported in this platform
/sys/kernel/debug/lmh_monitor/lmh-profile/available_levels
  - Lists the available profile levels for this platform.

CRs-Fixed: 704088
CRs-Fixed: 698387
Change-Id: I9afb9b8ef8532d8af383b9afc039654a2d550af4
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>