powerpc/p2041: configure the CPLD lane_mux according to RCW

powerpc/p2041: configure the CPLD lane_mux according to RCW

Lane muxing on p2041 is controlled by a reg in CPLD, offset of this reg
is 0xc, CPLD supports SATA by default, we should re-configure the lane
muxing according to RCW, which indicates what SerDes protocol it is running.

Default lane muxing map is as below:
Lane G on bank1 routes to SGMII, controlled by bit 1 of the reg;
Lane A on bank2 routes to AURORA, controlled by bit 0 of the reg;
Lane C/D on bank2 routes to SATA0 and SATA1, controlled by bit 2
and bit 3 respectively.

Default value of these bits for lane muxing is '1', we should set or clear
these bits accoring to RCW.

Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Acked-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>