ARM: dts: msm: Correct CX_DBGC_CFG register block name for sdmmagpie

CX_DBGC_CFG block was renamed from "kgsl_3d0_cx_dbgc_memory"
to "cx_dbgc" to make it more consice. Update this block name
so that it can be accessed.

Change-Id: I468aa8eaa6e90fde04f3d2c175e6bb743af83588
Signed-off-by: Deepak Kumar <dkumar@codeaurora.org>