IMC uncore unit can only be accessed via MMIO on Snow Ridge.
The MMIO space of IMC uncore is at the specified offsets from the
MEM0_BAR. Add snr_uncore_get_mc_dev() to locate the PCI device with
MMIO_BASE and MEM0_BAR register.

Add new ops to access the IMC registers via MMIO.

Add 3 new free running counters for clocks, read and write bandwidth.
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: eranian@google.com
Link: https://lkml.kernel.org/r/1556672028-119221-7-git-send-email-kan.liang@linux.intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>