ARM: rmobile: beacon-renesom: Enable QSPI NOR Flash

There is a QSPI NOR flash part on the board.  Because this chip isn't
yet supported in Linux, but it is supported in U-Boot, and the
face that the RPC_SPI compatible names are different in U-Boot and
Linux, the device tree updates are confined to -u-boot.dtsi files.

In order to use the QSPI, TF-A must leave RPC unlocked by compiling
TF-A with RZG_RPC_HYPERFLASH_LOCKED=0.

Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Biju Bas <biju.das.jz@bp.renesas.com>