The current work on arm branch.

The current work on arm branch, all page table stuff done, ready for the next step.

Choose one (Mandatory):

[x] This PR is for a code-review and is intended to get feedback, but not to be pulled yet.
[ ] This PR is mature, and ready to be integrated into the repo.

@phanikishoreg @ryuxin

As part of this pull request, I've considered the following:

[x] Comments adhere to the Style Guide (SG)
[x] Spacing adhere's to the SG
[x] Naming adhere's to the SG
[x] All other aspects of the SG are adhered to, or exceptions are justified in this pull request
[ ] I have run the auto formatter on my code before submitting this PR (see doc/auto_formatter.md for instructions)

[x] I've made an attempt to remove all redundant code Some redundant code regarding page table operations is mot removed in capinv.c. All of these code lines are surrounded with / TODO:remove after testing / block comments, and will be removed after Phani's comprehensive testing of kernel APIs.
[x] I've considered ways in which my changes might impact existing code, and cleaned it up
[x] I've formatted the code in an effort to make it easier to read (proper error handling, function use, etc...)
[x] I've commented appropriately where code is tricky
[x] I agree that there is no "throw-away" code, and that code in this PR is of high quality

I've tested the code using the following test programs (provide list here):

gwsystems / composite