So missing ARMv8.1/ARMv8.2/ARMv8.4 cases will cause
enable_monitor_mode() returns -ENODEV,and eventually
arch_hw_breakpoint_init() will fail.
Signed-off-by: Candle Sun <candle.sun@unisoc.com> Signed-off-by: Nianfu Bai <nianfu.bai@unisoc.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>