armv8/ls1043aqds: Select lpuart pins of various muxes

Set Board Configuration Register to select the lpuart pins of various
muxes.

Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Signed-off-by: Mingkai Hu <Mingkai.Hu@freescale.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: York Sun <york.sun@nxp.com>