drm/i915/mtl: Define mask for DDI AUX interrupts

Xe_LPD+ defines interrupt bits for only DDI ports in the DE Port
Interrupt registers. The bits for Type-C ports are defined in the PICA
interrupt registers.

BSpec: 50064

Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230428095433.4109054-10-mika.kahola@intel.com