Update dtc to commit 558cd81bdd432769b59bff01240c44f82cfb1a9d (tag
v1.4.4).

The DT overlay mechanism was added in v1.4.3 so an update of dtc was
needed. Update to v1.4.4 (latest version at the time) to have all
possible fixes.

In order to apply on a Device Tree an overlay that has a phandle to a
certain DT node, we need symbols in the DTB of the Device Tree to which
the overlay is applied.

Without the symbols, the tool in charge of applying the overlay cannot
find the DT node to apply the overlay to.

This adds the -@ option to the call to dtc which enables the generation
of symbols.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>

…rlays

Before DT overlays, we had a DT for each possible combination of
hardware. While there is mostly only support for different LCD at the
moment, the trade-off of this easy solution comes when you can have
multiple different hardwares at the same time, then the number of files
grows exponentially.

Now that we have support for DT overlays, move everything that can to DT
overlay and delete these DTs.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>

This fixes conflicts with PDA overlays since PC10-11 conflict with can0
and PC26-27 conflict with can1.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>

spi0 conflicts with isi. Disable it by default.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>