* Revert "Fix boot from 128GB Micron eMMC on ODROID-N2(+) (#1064)"
This reverts commit 162084082e.
This patches seem to cause issue on a ODROID-N2 with 32GB eMMC.
* Cap eMMC frequency to 24MHz in U-Boot for ODROID-N2(+)
Also remove the ODROID-C4 specific patch.