Revert "pkgbase: Create a FreeBSD-dtb package"

Somehow this doesn't work iwth make packages due to some kind of a race.
The package is first created correctly but later in the process it is
overwritten by a badly created empty package.
Revert in the mean time so we can have working pkgbase on arm/arm64

This reverts commit a5afd7920d50ff23f91bdbabb1f0fd7ba028ba9e.