kernel: default ARM_PMU on for armsr/armv8

CONFIG_ARM_PMU (Arm Performance Monitor Unit) is a requirement
to use KVM (virtualization) from Linux 5.11+, as the virtualised
guest has virtualized PMU access.

Signed-off-by: Mathew McBride <[email protected]>

config/Config-kernel.in

@@ -47,6 +47,7 @@ config KERNEL_MIPS_FP_SUPPORT
 
 config KERNEL_ARM_PMU
 	bool
+	default y if TARGET_armsr_armv8
 	depends on (arm || aarch64)
 
 config KERNEL_X86_VSYSCALL_EMULATION