ARM: dts: msm: modify SKUIC dts to support 512M memory

The memory size of SKUIC board is 512M, so update the dts file
accordingly.

Change-Id: I83ab1b63811ac1f8d5f458f4c1eb4b92ffd45e38
Signed-off-by: Mao Jinlong <c_jmao@codeaurora.org>