arm64: Kconfig: drop KAISER reference from KPTI option description

KAISER is a reference to the KASLR hardening technique that already
existed before Meltdown happened, and by now, it is sufficiently obscure
that mentioning it does not actually clarify anything. So remove this
reference, and replace it with KPTI.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20231127120049.2258650-8-ardb@google.com


Signed-off-by: Will Deacon <will@kernel.org>