U-Boot: disable optimisation to help debugging

* the U-Boot support code is yet unfinished and needs more debugging.
Merge branch 'master' into sam460ex
Add libfdt from dtc v1.3.0

* U-Boot based loader code will need to manipulate the passed
Flattened Device Tree, no need to reinvent the wheel.
* libfdt itself is dual-licensed GPL/BSD, the later suiting us.
* This comes from <git://git.jdl.com/software/dtc.git> tag v1.3.0
libfdt: Move headers to headers/libs/libfdt
haiku_loader: add memchr to the list of imported libroot objects

* libfdt uses memchr, so add this function from the libroot objects
U-Boot: compile and link to libfdt

* For the sam460ex and likely some ARM boards we will try to boot
using the passed FDT, as it's the recommended method now.
U-Boot: dump the passed FDT

* add some helpers for Flattened Device Trees, for now a dump call
* dump the passed FDT on startup for now
Merge branch 'master' into sam460ex
U-Boot: don't dump the FDT nodes by default

* only dump some header infos from the FDT by default, as dumping
the complete tree can get quite verbose.
U-Boot: initialize the debug UART using FDT hints when possible

* we first try to find 'serial', 'serial0' or 'serial1' in /aliases
* extract the required properties from the found node and use them
* fallback to the hardcoded UART from the board definition header
U-Boot: fix hex dump in fdt support
U-Boot: check for /chosen in the FDT for an initrd holding our tgz

* since the FDT linux boot method doesn't pass the uimage, we can't
use it to pass the kernel+driver tgz in a multi-file uimage.
* instead we check for the linux initrd properties in the /chosen node.
Merge branch 'master' into sam460ex
Merge branch 'master' into sam460ex
Merge branch 'master' into sam460ex
Merge branch 'master' into sam460ex
Merge branch 'master' into sam460ex
Merge branch 'master' into sam460ex
Merge branch 'master' into sam460ex
Add arch_framebuffer.h for ppc

* should fix the build