drm/i915/display: Use _PICK_EVEN_2RANGES() in DP AUX regs

XELPDP_DP_AUX_CH_CTL() and XELPDP_DP_AUX_CH_DATA() use 2 ranges. Prefer
using _PICK_EVEN_2RANGES() over PICK().

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230919192128.2045154-11-lucas.demarchi@intel.com