drm/i915/display: Group PSR2 prog sequences and workarounds

drm/i915/display: Group PSR2 prog sequences and workarounds

Grouping inside of the same if all the programing sequences and
workarounds of PSR2.
The order of programing changed in intel_psr_enable_source() but
it will not affect PSR2 as at this point PSR2_ENABLE is still disabled.

Cc: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220210185223.95399-1-jose.souza@intel.com