KVM: ARM: Fix typo in comments of inject_abt()

Very minor typo in comments of inject_abt() when we update fault status
register for injecting prefetch abort.

Signed-off-by: Anup Patel <anup.patel@linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>