CHROMIUM: staging:rts_pstor: Enable ASPM L0s & L1 by default.

CHROMIUM: staging:rts_pstor: Enable ASPM L0s & L1 by default.

Enable ASPM's L0s and L1 to save power when device is idle.

BUG=chrome-os-partner:15258
TEST=manual,
Boot device &
  lspci -vvv | egrep -i "^[0-9]|lnkctl"

Look for Realtek sdcard reader and that the link control says:
  LnkCtl: ASPM L0s L1 Enabled; ...

Change-Id: Ide6fbdeff0a3212639dc2ba85c7b5c43ba3574fe
Signed-off-by: Todd Broch <tbroch@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/35701
Reviewed-by: Sameer Nanda <snanda@chromium.org>