When ARMv8 cores are used in AArch32 mode, arch_hw_breakpoint_init()
in arch/arm/kernel/hw_breakpoint.c will be used.

From ARMv8 specification, v8 debug architecture versions defined:
* 0110 ARMv8, v8 Debug architecture.
* 0111 ARMv8.1, v8 Debug architecture, with Virtualization Host
  Extensions.
* 1000 ARMv8.2, v8.2 Debug architecture.
* 1001 ARMv8.4, v8.4 Debug architecture.

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>