iommu/arm-smmu: enhance tlb sync timeout handler

Enhance TLB sync timeout handler. Parse debug registers to identify TBU/TCU
invalidation or SYNC pending state and dump appropriate TBU testbus data
accordingly.

Example output:
arm-smmu 15000000.apps-smmu: TLB sync timed out -- SMMU may be deadlocked
TBU ACK 0x3f0000 TBU PWR 0x3f TCU sync_inv 0x1000d5
arm-smmu 15000000.apps-smmu: TCU invalidation completed, TCU sync pending
arm-smmu 15000000.apps-smmu: TBU PWR status 0x3f
arm-smmu 15000000.apps-smmu: TBU sync ack pending for TBU
150d9000.adsp_tbu, check pending transactions on TBU.

Change-Id: If9ca9dcaf26f06ee9b4204771631425cec52f95b
Signed-off-by: Prakash Gupta <guptap@codeaurora.org>
Signed-off-by: Chris Goldsworthy <cgoldswo@codeaurora.org>