ARM: spectre-v2: KVM: invalidate icache on guest exit for Brahma B15

Commit 3c908e16396d130608e831b7fac4b167a2ede6ba upstream.

Include Brahma B15 in the Spectre v2 KVM workarounds.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>