arm64: dts: juno: Fix SCPI shared mem node name

The SRAM DT binding requires child nodes to use a certain node name
scheme.

Change the naming from scp-shmem to scp-sram to comply with that.

Link: https://lore.kernel.org/r/20200513103016.130417-19-andre.przywara@arm.com


Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>