refactor(plat/rcar3): factor out DT memory node generation

Move the code that adds single new memory@ node into the DT fragment passed
to system software into separate function. Adjust the failure message to be
more specific and print the address range of node which failed to be added.
No functional change.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Change-Id: Ie42cd7756b045271f070bca93c524fff6238f5a2
1 file changed