ARM: renesas: Rename CONFIG_ARCH_RMOBILE_EXTRAM_BOOT to CONFIG_RENESAS_EXTRAM_BOOT

Rename CONFIG_ARCH_RMOBILE_EXTRAM_BOOT to CONFIG_RMOBILE_EXTRAM_BOOT
because the former symbol does not exist and it is only incorrectly
converted CONFIG_RMOBILE_EXTRAM_BOOT which does exist. Replace the
RMOBILE with RENESAS because all the chips are made by Renesas, while
only a subset of them is from the R-Mobile line.

Use the following command to perform the rename with manual Kconfig.32 fix:

"
$ sed -i 's@CONFIG_ARCH_RMOBILE_EXTRAM_BOOT@CONFIG_RMOBILE_EXTRAM_BOOT@g' board/renesas/*/*
$ sed -i 's@CONFIG_RMOBILE_EXTRAM_BOOT@CONFIG_RENESAS_EXTRAM_BOOT@g' board/renesas/*/*
"

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Paul Barker <paul.barker.ct@bp.renesas.com>