reform-boundary-uboot

DDR erratum A008336 only applies to DDR controller v5.2.0.
DDR controller v5.2.1 already has default 0x43b30002 in
EDDRTQCR1 register for optimal performance.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>