drm/i915/tgl+: Fix interrupt handling for DP AUX transactions

Unmask/enable AUX interrupts on all ports on TGL+. So far the interrupts
worked only on port A, which meant each transaction on other ports took
10ms.

Cc: <stable@vger.kernel.org> # v5.4+
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200504075828.20348-1-imre.deak@intel.com