arm64: dts: ti: k3-am69-sk-ddr-mem-carveout: Fix overlay format

commit 284edcfcb4b8e2cb77d9548666fdac1b310154ca from
git://git.ti.com/ti-linux-kernel/ti-linux-kernel.git



Remove the redundant fragment node in the DDR carveout memory overlay file.

Fixes: cc6651b1cfbc ("arm64: dts: k3-am69-sk: Add overlay for DDR carveout memory nodes")

Signed-off-by: Dasnavis Sabiya <sabiya.d@ti.com>
Signed-off-by: Xulin Sun <xulin.sun@windriver.com>