Make Marvell armv7 timer and wdt registers defined in mvreg.h generic

[mkm_semihalf.com]

Summary

Define timers registers for both SoC and choose proper one during runtime
based on information from FDT.
In WDT driver there are different function for ArmadaXP and others SoCs.
In timer driver registers definitions are stored in resource_spec structure
and choose during runtime.