arm: rpi: Set dtbs as the default target

Issue infrastructure/apertis-issues#221 (closed)

Commit cf90c49f ("d/patches: arm: rpi: Emit dtbs by default for arm64 rpi platforms") enabled dtbs to be built by default on rpi platforms. In order to do so, it disabled the OF_BOARD config option, which causes the dram_init_banksize() function to be dicarded, thus DRAM memory size is not detected properly, e.g. the CANOPi board reports 948 MiB instead of 1.9 GiB.

This commit reverts the offensive patches, reenabling the required OF_BOARD config option. Instead, another workaround is introduced to get the dtbs built by default on these platforms by setting dtbs in the default target configuration.

Signed-off-by: Ariel D'Alessandro ariel.dalessandro@collabora.com