feat(rdn2): enable AMU if present on the platform

Set build-option ENABLE_FEAT_AMU to 2 so that AMU is enabled if the
feature is implemented on the platform. This would ensure that lower ELs
could access system registers relevant to AMU without causing a trap to
EL3.

Signed-off-by: Rohit Mathew <rohit.mathew@arm.com>
Change-Id: Ic9aa435af54eddacdaa49e69f25893ddaa977e3e
1 file changed