Tegra: fdt: Remove memreserve line from Cardhu/Seaboard DT files

Not used, and wrong in Cardhu's case

Signed-off-by: Tom Warren <twarren@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>

board/nvidia/dts/tegra20-seaboard.dts

@@ -1,6 +1,5 @@
 /dts-v1/;
 
-/memreserve/ 0x1c000000 0x04000000;
 #include "tegra20.dtsi"
 
 / {

board/nvidia/dts/tegra30-cardhu.dts

@@ -1,6 +1,5 @@
 /dts-v1/;
 
-/memreserve/ 0x1c000000 0x04000000;
 #include "tegra30.dtsi"
 
 / {