Don't use 'xe_lp*' prefixes for register lists that are common with
Gen8.

Don't add Xe only GSC registers to pre-Xe devices that don't
even have a GSC engine.

Fix Xe_LP name.

Don't use GEN9 as a prefix for register lists that contain all GEN8
registers.

Rename the 'default_' register list prefix to 'gen8_' as that is the
more accurate name.
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230428185636.457407-4-John.C.Harrison@Intel.com