drm/i915: Define SEL_FETCH_PLANE registers via PICK_EVEN_2RANGES()

drm/i915: Define SEL_FETCH_PLANE registers via PICK_EVEN_2RANGES()

Instead of that huge _PICK() let's use PICK_EVEN_2RANGES()
for the SEL_FETCH_PLANE registers. A bit more tedious to have
to define 8 raw register offsets for everything, but perhaps
a bit easier to understand since we use a standard mechanism
now instead of hand rolling the arithmetic.

Also bloat-o-meter says:
add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-326 (-326)
Function                                     old     new   delta
icl_plane_update_arm                         510     446     -64
icl_plane_disable_sel_fetch_arm.isra         158      54    -104
icl_plane_update_noarm                      1898    1740    -158
Total: Before=2574502, After=2574176, chg -0.01%

v2: s/mtl+/tgl+/ comments to reflect actual reality

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240516135622.3498-7-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>