armv8: psci: add ARMV8_PSCI_RELOCATE Kconfig option

armv8: psci: add ARMV8_PSCI_RELOCATE Kconfig option

There is an user-selectable SYS_HAS_ARMV8_SECURE_BASE, which has the
same meaning but is just for the ls1043ardb board. As no in-tree config
uses this, drop it and replace it with something more sophiticated:
ARMV8_PSCI_RELOCATE. This option will then enable the ARMV8_SECURE_BASE
option which is used as the base to relocate the PSCI code (or any code
in the secure region, but that is only PSCI). A SoC (or board) can now
opt-in into having such a secure region by enabling
SYS_HAS_ARMV8_SECURE_BASE. Enable it for the LS1043A SoC, where it was
possible to relocate the PSCI code before as well as on the LS1028A SoC
where there will be PSCI support soon.

Additionally, make ARMV8_PSCI and SEC_FIRMWARE_ARMV8_PSCI exclusive.

Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>