feat(debugv8p9): test if EL3 has properly enabled FEAT_Debugv8p9

When FEAT_Debugv8p9 is not enabled, access to MDSELR_EL1
traps to EL3. Access to FEAT_DEBUGV8P9 control registers
must be explicitly enabled in EL3,

This testcase uses this behavior to test if
FEAT_Debugv8p9 is enabled or not.

Change-Id: I2f9a0158e9f38eaffac2e27c40d44d3c520d508d
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
6 files changed