As per latest mailing communication [1], we decided
not to update SCTLR and TCR registers in EL1 and EL2 context
restore routine when AT speculative workaround is enabled
hence reverted the changes done as part of this commit: 45aecff00.

[1]:
https://lists.trustedfirmware.org/pipermail/tf-a/2020-July/000586.html

Change-Id: I8c5f31d81fcd53770a610e302a5005d98772b71f
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>