ARM64: smp: Prevent cluster LPM modes when pending IPIs on cluster CPUs

LPM modes can fail if there is a pending IPI interrupt at GIC CPU
interface. On some usecases frequent failure of LPM modes can cause
power and performance degradation. Hence, prevent cluster low power
modes when there is a pending IPI on cluster CPUs.

This patch has been combined with the following patches:
	- 'commit c3d3af5dce1fb52 ("ARM: smp: Remove use of
	  IPI_CALL_FUNC_SINGLE")'
	- 'commit 0a061eca16bf0d8 ("ARM: kernel: smp: Clear Pending IPI
	  flag after handling")'

Change-Id: Id8a0ac24e4867ef824e0a6f11d989f1e1a2b0e93
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>
Signed-off-by: Murali Nalajala <mnalajal@codeaurora.org>
[satyap: trivial merge conflict resolution]
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>