soc: mediatek: mtk-svs: Convert sw_id and type to enumerations

The sw_id and type specifiers currently are defined as BIT(x) for
unknown reasons: nothing in this code makes any AND/OR check for
those, and that would never happen anyway because both sw_id and
type are exclusive, as in:
 - There will never be a bank that is for both CPU and GPU, or
   for CPU and CCI together;
 - A bank cannot be contemporarily of one-line and two-line type,
   as much as it cannot contemporarily have both HIGH and LOW roles

Change those definitions to enumerations and also add some kerneldoc
to better describe what they are for and what they indicate.

While at it, also change the names adding _SWID or _TYPE to increase
human readability.

Link: https://lore.kernel.org/r/20231121125044.78642-4-angelogioacchino.delregno@collabora.comSigned-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>