misc: rtsx: Add power saving functions and fix driving parameter

v4:
split power down flow and power saving function to two patch

v5:
fix up modified change under the --- line

Add rts522a L1 sub-state support
Save more power on rts5227 rts5249 rts525a rts5260
Fix rts5260 driving parameter

Signed-off-by: Ricky Wu <ricky_wu@realtek.com>
Link: https://lore.kernel.org/r/20200907100731.7722-1-ricky_wu@realtek.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>