Revert "FROMLIST: arm64: mte: move register initialization to C"

This reverts commit c4ebf715.
This change fails to restore MAIR_EL1 when coming back from suspend,
and causes MTE / KASAN false positives and other issues.

Bug: 239834217
Bug: 244409576
Signed-off-by: Evgenii Stepanov <eugenis@google.com>
Change-Id: I7b87d2bc479c749dd268d3b728535925bfac4e07