All build scripts use $BR2_ARCH to determine location of critical board files
and configuration. As per previous decisions, the BR2_ARCH variable controls
all naming in Infix and for consistency the defconfig files are also renamed.
This fixes the issue with missing DTB file(s) for the Raspberry Pi 2B.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
