We need to access reg stp_rep9, but not stp_rep[(9 - 1) / 2].
If using "__raw_writel(0, DI_STP_REP(disp, 9))", this will exceeds
the size of stp_rep array.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Acked-by: Liu Ying <Ying.Liu@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Anatolij Gustschin <agust@denx.de>