Revert "feat(sgi): deviate from arm css common uart related defi..."

Revert submission 14286-uart_segregation

Reason for revert: Need to wait for companion patches in CI and UEFI/Linux to be upstreamed.

Reverted Changes:
I8574b31d5:feat(sgi): add page table translation entry for se...
I8896ae05e:feat(sgi): route TF-A logs via secure uart
I39170848e:feat(sgi): deviate from arm css common uart relate...

Change-Id: I28a370dd8b3a37087da621460eccc1acd7a30287