Load address of tb_fw_config is incorrectly mentioned
in below device trees:
1. rdn1edge_fw_config.dts
2. tc0_fw_config.dts

Till now, tb_fw_config load-address is not being retrieved from
device tree and hence never exeprienced any issue for tc0 and
rdn1edge platform.

For tc0 and rdn1edge platform, Load-address of tb_fw_config should
be the SRAM base address + 0x300 (size of fw_config device tree)
Hence updated these platform's fw_config.dts accordingly to reflect
this load address change.

Change-Id: I2ef8b05d49be10767db31384329f516df11ca817
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>