rockchip: odroid-go2: Use env from same storage FIT was loaded from

rockchip: odroid-go2: Use env from same storage FIT was loaded from

Change to dynamically select what storage media to use for the U-Boot
environment depending on from what storage media the FIT images was
loaded from, fall back to use env from nowhere.

  U-Boot SPL 2025.07 (Jul 13 2025 - 10:07:16 +0000)
  Trying to boot from MMC1
  ...
  Loading Environment from MMC... Reading from MMC(0)...

or

  U-Boot SPL 2025.07 (Jul 13 2025 - 10:07:16 +0000)
  Trying to boot from SPI
  ...
  Loading Environment from SPIFlash...

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>