Documentation/kvm/arm: improve description of HVC_SOFT_RESTART

Documentation/kvm/arm: improve description of HVC_SOFT_RESTART

Besides disabling MMU, HVC_SOFT_RESTART also clears I+D bits. These behaviors
are what kexec-reboot expects, so describe it more precisely.

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: linux-doc@vger.kernel.org
Cc: kvmarm@lists.cs.columbia.edu
Link: https://lore.kernel.org/r/1598621998-20563-2-git-send-email-kernelfans@gmail.com
To: linux-arm-kernel@lists.infradead.org
Signed-off-by: Will Deacon <will@kernel.org>