firmware: arm_scpi: allow firmware with get_capabilities not implemented

On Amlogic SCPI legacy implementation, the GET_CAPABILITIES command is
not supported, failover by using 0.0.0 version.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
[sudeep.holla@arm.com: changed the subject]
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>