platform/x86: asus-wmi: name the TUF keyboard RGB state and speed codes

The TUF keyboard RGB attributes encode four power-state flags and three
animation speeds as bare BIT() and hex literals inside their store
handlers.  The speed codes in particular read as arbitrary hex until
one knows they are EC firmware conventions: 0xe1, 0xeb and 0xf5 select
animation step thresholds of 30, 20 and 10 ticks per phase, which the
EC derives from the stored byte through a lookup table.

Give the seven values names and use them in kbd_rgb_mode_store() and
kbd_rgb_state_store(), so the handlers state what they mean without a
decoding comment.  No behavior change.

Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bartu Alev <bartualev@gmail.com>
Link: https://patch.msgid.link/20261010101601.888709-4-bartualev@gmail.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>