configs: rv1126b-ipc: Update uboot.img size as 512KB*1

Signed-off-by: Joseph Chen <chenjh@rock-chips.com>
Change-Id: If128bee2d4db2b8835652c9c74ef420fab616c38

rockchip: Add rv1126b Soc support

Change-Id: Iba57b03a8fe9bd8dfb2853a1748192feb8a7fe4c
Signed-off-by: Xuhui Lin <xuhui.lin@rock-chips.com>